Valve Seal Curved Surface Geometry for High-Temperature Shutoff

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Solution Overview

Problem

Valves used in high-temperature industrial processes face challenges in achieving tight shutoff due to the limitations of both soft seals, which burn at elevated temperatures, and metal seals, which cannot maintain tight shutoff when cooled from high temperatures, leading to potential leaks and operational issues.

Innovation Solution

A ring-shaped cartridge seal with compressible graphite laminate layers and curved surfaces that allow for initial contact with a flow control member on a sealing surface, maintaining tight shutoff throughout temperature changes without the need for expensive actuators.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If soft seals (e.g., PTFE) are used in high temperature conditions, then the valve can achieve tight shutoff, but the seal material burns or sublimes when exposed to temperatures exceeding 450 degrees Fahrenheit

Engineering Contradiction:

Improvetight shutoff capabilityVSAvoidtemperature resistance

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The seal combines a metal ring structure with a PTFE coating layer, creating a composite material that leverages the high-temperature resistance of metal and the sealing capability of PTFE. The metal ring provides structural integrity at elevated temperatures while the PTFE coating maintains tight shutoff capability.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The seal design incorporates a curved surface geometry that changes the contact parameters between the seal and flow control member. The curved surface enables proper sealing contact while accommodating thermal expansion and contraction, maintaining sealing effectiveness across temperature variations.

Inventive Principle:

Principle #35Parameter changes

2Temperature

If metal seals are used in high temperature conditions, then the seal can withstand elevated temperatures, but the seal cannot achieve tight shutoff

Engineering Contradiction:

Improvetemperature resistanceVSAvoidtight shutoff capability

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The seal applies PTFE coating only to the specific sealing surface areas where contact with the flow control member occurs, while the rest of the metal ring structure provides thermal resistance. This localized application of different material properties optimizes both sealing and temperature resistance.

Inventive Principle:

Principle #3Local quality

3Reliability

If a triple offset valve design is used to achieve tight shutoff at high temperatures, then the valve can maintain sealing, but the valve requires an expensive, large actuator to drive the flow control member

Engineering Contradiction:

Improvetight shutoff capabilityVSAvoidactuator size and cost

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The seal incorporates curved surfaces on the metal ring that match the geometry of the flow control member. This curvature design enables automatic centering and proper sealing contact with minimal actuator force, eliminating the need for large, expensive actuators required by traditional triple offset designs.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The curved surface geometry of the seal enables the flow control member to automatically align and compress the seal material into the correct sealing position during operation, without requiring complex actuation mechanisms or large actuators to force alignment.

Inventive Principle:

Principle #25Self-service

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 seal achieves ANSI Class VI shutoff at high temperatures and maintains performance when cooled to ambient temperatures, reducing leaks and operational issues while avoiding the need for costly actuators.

Implementation Method 1

The first and second curved surfaces enable a flow control member to compress the sealing portion prior to contacting the curved surfaces as the flow control member transitions to a closed position

Methodology Applied

Scientific EffectCompression: Compression

Implementation Method 2

In high temperature conditions, metal seals are often used because softer, non-metallic seals (e.g., a polytetrafluoroethylene seal) may sublimate or burn when exposed to temperatures exceeding 450 degrees Fahrenheit

Methodology Applied

Scientific EffectThermal stability: Thermal Insulation

Data Source

PatentUS9568110B2Valve seals

Publication Date: 2017.02.14 FISHER CONTROLS INT LLC

AI summary

Valve seals are described. An example seal for use in a valve includes a ring-shaped cartridge having a first portion, a second portion opposite the first portion, and a compressible sealing portion between the first and second portions. The first and second portions have respective first and second curved surfaces adjacent a sealing surface of the compressible sealing portion. The first and second curved surfaces enable a flow control member to compress the sealing portion prior to contacting the curved surfaces as the flow control member transitions to a closed position.