Rotary Valve Seal Ring Assembly with Compressive Fasteners
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Solution Overview
Problem
Rotary valves face challenges with seal blowout under high pressure and flow conditions, leading to loss of shut-off capability due to fluid forces overcoming frictional and adhesive forces retaining the seal.
Innovation Solution
A seal ring assembly with a ring-shaped seal made of expanded graphite, compressed between first and second seal clamps, with fasteners extending through the seal to maintain compressive force, and optionally segmented clamps and spring wires to reduce torque requirements and ensure tight shutoff.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a metal seal is used, then the seal can withstand high temperature and high pressure, but the seal is more susceptible to wear
Solution Approach 1:
The patent employs a composite sealing structure combining a metal seal ring with a PTFE sealing layer. The metal substrate provides high temperature and pressure resistance, while the PTFE coating delivers low friction and wear resistance, achieving both high-temperature capability and durability simultaneously
2Ease of operation
If a PTFE seal is used, then the seal provides excellent sealing performance and requires less torque, but the seal is limited to temperatures below 232.22°C
Solution Approach 1:
The patent creates a composite seal where PTFE is applied as a coating layer on a metal substrate. This allows the seal to operate at temperatures above 232.22°C while the PTFE layer maintains low friction and torque requirements, extending the operational temperature range beyond pure PTFE limitations
3Temperature
If a graphite laminated seal is used, then the seal can withstand high temperatures and provides excellent shutoff, but the seal structure is more complex
Solution Approach 1:
The patent uses a metal seal ring with PTFE coating, which achieves high-temperature capability through the metal substrate without requiring the complex laminated structure of graphite seals. The simple two-layer composite structure reduces manufacturing complexity while maintaining temperature resistance and sealing performance
4Reliability
If a triple offset valve is used, then the valve reduces wear through angled geometry, but the valve requires high torque to engage the control member and seal
Solution Approach 1:
The patent employs a composite seal structure with PTFE coating on metal substrate that provides both wear resistance and low friction. This combination reduces the torque required for engagement compared to triple offset valves, while the PTFE layer maintains durability and wear resistance through its self-lubricating properties
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 effectively maintains seal integrity under high-pressure conditions, reducing torque needed for tight shutoff and preventing seal blowout, while allowing for flexible expansion and contraction of the seal.
Implementation Method 1
a plurality of fasteners extending through the seal and fixed to the first and second seal clamps to maintain a compressive force on the seal
Implementation Method 2
The seal is made of expanded graphite and allows for flexible expansion and contraction of the seal
Data Source
Figure 1
Figure 2
Figure 3~5
AI summary
Seal ring assemblies for use with rotary valves and methods to manufacture the same are disclosed. A seal ring assembly (108) is described that includes a ring-shaped seal (112) to be fixed within the rotary valve, where the seal enables the sealing engagement of a control member with a flow control aperture. The seal is compressed between a first seal clamp (114) and a second seal clamp (116) by a compressive force maintained by a plurality of fasteners (118) extending through the seal and fixed to the first and second seal clamps.