Fire-Safe Ball Valve Sealing With Metal Backup Ring
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Solution Overview
Problem
Ball valves with polymeric sealing rings fail to maintain a closed condition between inlet and outlet during fires due to poor high-temperature resistance, leading to fluid leakage, and existing regulations require these valves to remain closed for at least thirty minutes to allow firefighters to intervene.
Innovation Solution
A ball valve design featuring a polymeric sealing ring supported by a metal support ring with a frustoconical contact surface and an elastic influencing portion that maintains a fluid seal even if the sealing ring melts, utilizing a shape coupling mechanism to ensure contact with the shutter surface and absorb overpressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polymeric sealing rings are used between the shutter and valve body, then the valve provides effective sealing under normal conditions, but the sealing rings lose consistency or melt at high temperatures during fires, causing fluid leakage
Solution Approach 1:
The patent combines polymeric sealing rings with metal support rings to create a composite sealing system. The polymeric material provides effective sealing under normal conditions, while the metal support ring provides structural stability and fire resistance. This composite structure allows the valve to maintain sealing performance both at normal operating temperatures and during fire conditions, resolving the contradiction between sealing effectiveness and high-temperature resistance.
2Reliability
If polymeric sealing rings are used, then sealing is achieved under normal conditions, but the valve fails to maintain closed condition for the required thirty minutes during fire conditions
Solution Approach 1:
The composite structure of polymeric sealing rings combined with metal support rings ensures that the valve maintains its closed condition for the required thirty minutes during fire conditions. The metal support ring prevents collapse of the sealing structure under high temperature, while the polymeric material maintains sealing effectiveness, thereby extending the functional duration during fire emergencies.
Solution Approach 2:
The metal support ring acts as a pre-positioned structural reinforcement that prevents the sealing system from failing under high-temperature stress. By providing this structural cushioning in advance, the system ensures that even when the polymeric material is exposed to fire temperatures, the overall sealing structure remains intact and functional for the required duration.
3Strength
If a simple polymeric sealing ring is used, then the device structure remains simple, but the valve cannot withstand overpressure conditions without damage
Solution Approach 1:
The combination of polymeric sealing rings with metal support rings creates a sealing device that can withstand overpressure conditions. The metal support ring provides the necessary structural strength to resist high pressure, while the polymeric material maintains the sealing function. This composite approach increases overpressure resistance while adding only moderate complexity to the sealing device structure.
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 valve effectively maintains a fluid seal during high-temperature conditions, including fires, and withstands overpressure without damage, while also reducing the torque required for operation and tolerating scale formation and low temperatures.
Implementation Method 1
an elastic influencing portion that maintains a fluid seal even if the sealing ring melts
Implementation Method 2
a frustoconical contact surface and an elastic influencing portion that maintains a fluid seal even if the sealing ring melts, utilizing a shape coupling mechanism to ensure contact with the shutter surface and absorb overpressure
Data Source
AI summary
A valve for intercepting a fluid in a duct is provided. The valve has a valve body, a ball shutter, and a sealing device for forming a fluid seal with an external surface of the ball shutter. The sealing device has a polymeric sealing ring located in contact with the external surface, and a metal support ring coupled to the sealing ring. The support ring has an annular coupling portion having an annular contact portion formed by a frustoconical wall, and an elastically bendable influencing portion, so as to form an elastic lever. In an emergency condition in which the sealing ring is absent the annular contact portion is in contact with the external surface of the ball shutter due to at least fluid pressure, forming the fluid seal even in the emergency condition.