Fluoropolymer-Coated Ball Valve Coupling for Leak-Free Corrosion Resistance
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Solution Overview
Problem
Conventional ball valves with detachable corrosion-resistant fluoropolymer coatings face damage from direct transmission of operating forces, leading to reduced corrosion resistance, while integrated designs suffer from eccentric loads causing leakage.
Innovation Solution
A ball valve with a detachable coupling between the sealing member and operating spindle, featuring an uninterrupted fluoropolymer coating that surrounds both parts, including a tubular section extending beyond the sealing element, providing a dimensionally stable corrosion-resistant layer and a mechanical lock connection, such as a tongue/groove system, to prevent direct force transmission and ensure longer corrosion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sealing member and operating spindle are connected via a lock connection, then the sealing member is pressed against the seal by medium pressure (floating ball principle), but the operating forces are transmitted directly to the plastic coatings, causing damage and reduced corrosion resistance
Solution Approach 1:
The patent introduces an intermediary metal part (the operating spindle core) between the operating forces and the plastic coating. The metal spindle receives the operating forces from the handle and transmits them to the sealing member through a connection interface, preventing direct force transmission to the plastic coating and thus protecting it from damage while maintaining the floating ball sealing mechanism
Solution Approach 2:
The operating spindle is segmented into a metal core portion and a plastic coating portion. The metal core handles the mechanical forces and connections, while the plastic coating provides corrosion resistance only where needed. This segmentation allows the force-bearing and corrosion-resistant functions to be separated, protecting the plastic coating from damaging operating forces
2Duration of action of stationary object
If the sealing member and operating spindle are formed as a single part, then there is no risk of damage to the fluoropolymer coating from lock connection forces, but the ball displacement under medium pressure causes eccentric loading of the sealing kit, leading to leakage
Solution Approach 1:
The sealing member and operating spindle are segmented into separate components. The sealing member (ball) can move independently under medium pressure to maintain proper alignment with the sealing seats, while the operating spindle remains relatively stable for force transmission. This separation prevents the eccentric loading problem that occurs in integrated designs
3Ease of repair
If the operating spindle is detachably coupled to the sealing member, then the components can be separated for maintenance, but the connection interface requires additional sealing elements and increases device complexity
Solution Approach 1:
The connection interface between the operating spindle and sealing member uses homogeneous materials (metal-to-metal contact) for the force transmission elements, while the sealing function is handled by a single specialized sealing element. This approach simplifies the overall design by using appropriate materials for each function rather than complicating the force transmission path
Data Source
Figure 1
Figure 2~4
AI summary
The present invention relates to, on the one hand, a corrosion-resistant ball valve (15) comprising a housing (1; 2), in which a spherical sealing member (3) provided with a passage duct is rotatably arranged and an operating spindle (4) which is detachably coupled to the sealing member (3), in which the sealing member (3) is provided with an uninterrupted corrosion-resistant coating layer (16a), in which said coating layer comprises a tubular part (16b) which surrounds at least a part of the operating spindle (4). On the other hand, the present invention relates to a method for producing such a ball valve (15).