Double-Piston Ball Valve Seat Assembly for Seal Shift Control
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Solution Overview
Problem
Double piston effect seats in ball valve assemblies experience seal damage due to high pressure, leading to improper sealing, as the seals shift away from the ball under pressure differences.
Innovation Solution
A ball valve system design incorporating a seat assembly with a lantern ring positioned closer to the second end than the first, limiting seal movement and creating a double piston effect, which prevents the seal from shifting and maintaining contact with the ball even under pressure differences, using a spring to compress and maintain sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a seal is positioned between the seat and lantern ring in a double piston effect seat assembly, then the seal can move due to pressure differences, but this movement causes damage to the seals and improper sealing
Solution Approach 1:
The lantern ring is pre-positioned to define a limited travel space for the seal before pressure differences can cause excessive movement. This preliminary positioning constraint prevents the seal from moving beyond safe limits that would cause damage, while still allowing necessary movement for sealing function.
Solution Approach 2:
The lantern ring acts as an intermediary component between the seat and the seal, providing a physical boundary that limits seal movement. This intermediary structure protects the seal from direct exposure to uncontrolled pressure forces by confining it within a defined space.
2Reliability
If the lantern ring is positioned closer to the second end of the seat assembly, then seal movement is limited and sealing consistency is improved, but the structural design becomes more specific
Solution Approach 1:
The lantern ring is strategically positioned at a specific location (closer to the second end) rather than being centrally or uniformly distributed. This localized positioning creates the necessary constraint for seal movement limitation without requiring complex overall structural changes to the entire seat assembly.
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 ensures consistent sealing by preventing seal movement, protecting the seal from damage and maintaining fluid separation under varying pressures, enhancing the durability and reliability of the valve system.
Implementation Method 1
using a spring to compress and maintain sealing
Implementation Method 2
the seat, the lantern ring, and the seal are positioned in such a way that the seat assembly creates a double piston effect
Data Source
AI summary
A ball valve may include a body having an upstream end and a downstream end. A ball may be within the body between the two ends, the ball being rotatable about a vertical axis to move between an open position and a closed position. A ball valve may include a stem with a body and an actuator portion that enables the ball to be rotated between the open and closed positions. A ball valve may include a seat assembly with a first end facing towards the ball and a second end facing away from the ball, the seat assembly including a seat, the seat being in contact with the ball; a lantern ring, the lantern ring positioned closer to the second end of the seat assembly than the first end of the seat assembly; and a seal, the seal positioned between the seat and the lantern ring.