Polymeric Ball Valve Shrinkage Control via Segmented Half-Shells
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Solution Overview
Problem
The manufacturing of high-performing ball valves using polymeric materials is hindered by significant shrinkage issues in hot-moulding, resulting in irregularly shaped balls and high production costs due to the need for extensive machining and labor to achieve a regular shape.
Innovation Solution
A polymeric ball valve design featuring a ball with a varying section through hole and a structure composed of two half-shells connected by bridge areas, which reduces polymer volume and shrinkage, allowing for consistent thickness and maintaining the shape during moulding without additional tooling, thus reducing manufacturing time and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hot-moulding is used to manufacture polymeric balls, then production speed is improved, but the balls become irregularly shaped due to shrinkage
Solution Approach 1:
The ball is segmented into two half-shells connected by bridge areas, allowing each half to be moulded separately with controlled shrinkage. The bridge areas act as connectors that accommodate dimensional changes while maintaining the overall spherical shape, resolving the contradiction between rapid hot-moulding production and shape regularity.
Solution Approach 2:
The invention changes the geometric parameters of the ball by introducing a through hole with varying section and connecting the half-shells via bridge areas. This structural modification allows the ball to accommodate polymer shrinkage during hot-moulding while maintaining a regular external shape, enabling high-speed production without sacrificing precision.
2Manufacturing precision
If extensive machining and tooling are used to achieve regular ball shape, then manufacturing precision is improved, but production cost and time increase
Solution Approach 1:
The regular spherical shape is achieved during the moulding process itself through the preliminary design of the half-shell structure with bridge areas, rather than requiring post-moulding machining. This preliminary structuring accommodates shrinkage and maintains shape regularity, eliminating costly and time-consuming secondary operations.
Solution Approach 2:
The ball structure serves itself by using the bridge areas and varying section through hole to automatically accommodate shrinkage during hot-moulding. The design inherently compensates for dimensional changes without requiring external machining or tooling intervention, reducing manufacturing complexity and cost.
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 achieves a consistent, high-performance ball valve with reduced shrinkage and manufacturing costs by maintaining the shape of the ball during moulding, eliminating the need for post-moulding machining and tooling, while ensuring effective sealing and fluid control.
Implementation Method 1
the manufacture of this type of ball valves must necessarily take into account the considerable amount of shrinkage to which polymers are subjected after hot-moulding
Data Source
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AI summary
According to a first aspect, the invention relates to a ball (20) for a ball valve (1) suitable for controlling the flow in hydraulic systems. The ball comprises a through hole (21) defining a duct (22) for the flow, and defining an axis X. The ball is characterized in that the through hole has a section varying along the axis X. According to another aspect, the invention relates to a ball valve (1) comprising the ball described above.