Ceramic Ball Valve Assembly for Corrosive Tank Car Service
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Solution Overview
Problem
Current ball valve designs for railroad tank cars suffer from leakage due to contamination and corrosion, as well as issues with handles inadvertently opening during transport, leading to financial, business, and environmental consequences.
Innovation Solution
The implementation of a ceramic wiper and ceramic ball component to reduce scoring and corrosion, combined with a drive coupling for universal tool compatibility and a simplified stem packing assembly using a single wave spring for continuous compression, addresses the leakage and handle-related issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If TFE/PTFE valve seats are used, then sealing capability is improved, but susceptibility to contaminant embedding and ball component scoring increases
Solution Approach 1:
A ceramic wiper is introduced as an intermediary component between the contaminant-laden liquid and the valve seat/ball assembly. The wiper forms a barrier that prevents contaminants from embedding in the TFE/PTFE valve seat and scoring the ball component, while allowing the valve seat to maintain its sealing function against the ball.
Solution Approach 2:
The valve assembly uses a composite material approach by combining TFE/PTFE for the valve seat (providing sealing) with ceramic material for the wiper and ball component (providing abrasion and corrosion resistance). This composite structure leverages the advantages of each material while mitigating their individual weaknesses.
2Strength
If metal ball components are used, then structural strength is improved, but abrasion and corrosion resistance deteriorates
Solution Approach 1:
The invention transitions from pure metal ball components to ceramic ball components. Ceramic materials provide both the necessary structural strength and superior abrasion/corrosion resistance, eliminating the trade-off present in metal components. The ceramic material is inherently resistant to scoring by contaminants and corrosion from chemical liquid commodities.
3Ease of operation
If pre-attached handles are used, then ease of operation is improved, but risk of inadvertent opening during transport increases
Solution Approach 1:
The handle is extracted from the permanently attached state and converted into a removable component. The drive coupling allows the handle to be attached only when needed for operation, and removed during transport to eliminate the risk of inadvertent opening. This separates the operational function from the transport state.
4Reliability
If multiple stem packing components are used, then sealing effectiveness is improved, but device complexity increases
Solution Approach 1:
Multiple separate stem packing components are merged into a single integrated stem packing assembly. This unified component maintains the sealing effectiveness of multiple pieces while eliminating the complexity of assembling and maintaining separate components. The single assembly includes all necessary elements for effective stem sealing in an integrated 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 solution significantly reduces leakage and corrosion, enhances the durability of valve components, and ensures safe operation by preventing unintended opening of the valve during transport, while also reducing the number of components and maintaining effective sealing over time.
Implementation Method 1
a single wave spring forces a packing spacer and stem packing assembly against a stem
Implementation Method 2
Ceramics are much harder materials than steel and not easily abraded by contaminants
Implementation Method 3
They are also very resistant to corrosion by chemical liquid commodities carried in the tanks
Data Source
AI summary
Described herein is an improved ball valve assembly for use in a tank or a tank-like container. This improved ball valve assembly prevents leakage of a liquid with corrosive and abrasive contaminants within the tank or a tank like container. This improved ball valve assembly is especially useful in a railroad tank car that contains a liquid commodity in whenever a tank is mobile and subjected to wide temperature variations. The improved ball valve assembly contains a ball component made of a ceramic material. A ceramic wiper (i) mechanically seals against the ball component and (ii) prevents contaminants from embedding within, or otherwise abrading, top and bottom seats within the ball valve assembly. Also contained in the preferred embodiment of this invention is an improved drive coupling that (i) eliminates the previously existing need for custom square drive tool (ii) pre-attached to the ball valve assembly. The current invention also includes an improved stem packing assembly that reduces the number of annular components along the stem of the ball valve assembly.