Slotted-Ring Ball Valve Sealing for Double Isolation
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Solution Overview
Problem
Conventional non-relieving ball valves with graphite gaskets face difficulties in achieving double isolation, as the design does not allow fluid ingress below the contact line, limiting their application to only O-ring and lip-seal based systems, and are prone to damage due to over pressurization from temperature variations.
Innovation Solution
A non-pressure relieving ball valve design incorporating a slotted ring between the seat and sealing gasket, which allows pressurized fluid ingress to provide extra force for continuous abutment with the ball, preventing fluid flow from the valve cavity, and utilizing graphite or similar sealing materials to enhance sealing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional non-relieving ball valve design with graphite gaskets is used, then double isolation capability is achieved, but the valve is prone to over pressurization damage from temperature variations
Solution Approach 1:
The valve body is segmented into pressure-containing and non-pressure-containing portions. The non-pressure-containing portion includes the downstream end where thermal expansion occurs without generating damaging pressures. This segmentation allows the valve to maintain double isolation capability while preventing over pressurization damage from temperature variations.
2Object-affected harmful factors
If a pressure relieving mechanism is added to relieve over pressurization, then damage from temperature variations is prevented, but the double isolation capability is compromised
Solution Approach 1:
Instead of adding a pressure relieving mechanism that would compromise isolation, the design segments the valve body into pressure-containing and non-pressure-containing portions. The non-pressure-containing downstream end allows thermal expansion without generating damaging pressures, while maintaining continuous isolation capability through the seated ball and seat arrangement.
3Object-affected harmful factors
If the downstream end is designed as non-pressure containing to prevent over pressurization, then thermal expansion damage is avoided, but sealing requirements become more challenging
Solution Approach 1:
Different portions of the valve body have different pressure containing properties. The upstream end and ball cavity maintain pressure containment for isolation, while the downstream end is designed as non-pressure containing to accommodate thermal expansion. This local differentiation of pressure containment quality enables both thermal expansion management and effective sealing through appropriately designed seals at critical interfaces.
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 effectively restricts fluid flow at both upstream and downstream ends, reducing the risk of damage, improving valve performance, and reducing maintenance costs, while accommodating high and low temperature applications and customized requirements.
Implementation Method 1
The slotted ring of the non-pressure relieving ball valve is adapted to permit ingress of pressurized fluid in gaps, which are defined by the slotted ring to provide a desired extra force from back side of the seat towards the ball
Implementation Method 2
a seat which abuts the ball to restrict the leakage of the pressurized fluid when the ball is in a closed position
Implementation Method 3
a ball which is coupled to the stem and is configured to restrict flow of the pressurized fluid through the ball valve
Data Source
AI summary
A non-pressure relieving ball valve that includes: a stem connected to a handle regulating flow of pressurized fluid entering in the ball valve, a ball coupled to the stem and configured to control flow of the pressurized fluid through the ball valve, a seat abutting the ball to retain the in place, a sealing gasket provided in the ball valve and configured to restrict the flow of the pressurized fluid through the ball valve when the ball valve is in a closed position, and a slotted ring configured to be fitted in the ball valve between the seat and the sealing gasket. The slotted ring is adapted to permit ingress of pressurized fluid in slots defined on the slotted ring to enable balancing of fluid pressures on either side of the seat.