Valve Stem to Plug Connection via Threaded Joint and Weld
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Solution Overview
Problem
Existing methods for connecting a valve stem to a valve plug, such as welding or using a drive pin, can result in misalignment and integrity issues, especially when the materials are incompatible or non-weldable, affecting the valve's performance in controlling fluid flow.
Innovation Solution
The use of a weldable valve stem and a non-weldable valve plug, where the valve stem is threaded into the valve plug with a securement member or weld made in an adjacent opening to prevent rotation and ensure perpendicular alignment, thereby maintaining the integrity of the connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a drive pin is used to secure the valve stem to the valve plug, then non-rotatability is achieved, but misalignment occurs affecting valve plug integrity
Solution Approach 1:
A weld is introduced as an intermediary element between the valve stem and valve plug. The weld is deposited in a recess of the valve plug to secure the valve stem non-rotatably, while the threaded connection maintains perpendicular alignment. This intermediary welding process resolves the contradiction by achieving both non-rotatability and alignment that a drive pin alone cannot provide.
2Stability of the object's composition
If welding is used to fix the valve stem to the valve plug, then non-rotatability is achieved, but it cannot be applied when materials are non-weldable or incompatible
Solution Approach 1:
The connection mechanism is segmented into two independent functions: a threaded connection for alignment and positioning, and a separate welding connection for non-rotatability. This segmentation allows the threaded portion to handle material compatibility issues while the welding portion provides secure non-rotatable fixation, making the system adaptable to different material combinations.
Solution Approach 2:
The recess in the valve plug serves as an intermediary structure that accommodates the weld material. This recess design allows welding to be applied selectively when materials are compatible, while the threaded connection remains available as an alternative when materials are non-weldable, thus enhancing material compatibility versatility.
3Manufacturing precision
If the valve stem is threaded into the valve plug, then alignment is maintained, but non-rotatability is not achieved
Solution Approach 1:
Two connection methods are merged into a single integrated solution: the threaded connection provides precise perpendicular alignment, while the additional weld deposited in the recess provides non-rotatable security. This combination merges the advantages of both threading and welding, achieving both alignment and non-rotatability simultaneously.
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
This solution ensures proper alignment and secure non-rotatability of the valve stem to the valve plug, preventing misalignment and maintaining the valve's operational integrity, even with incompatible materials, and does not interfere with fluid flow.
Implementation Method 1
the valve stem is threaded into the valve plug with a securement member or weld made in an adjacent opening
Implementation Method 2
a securement member or weld made in an adjacent opening to prevent rotation
Data Source
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AI summary
Apparatus to connect a valve stem (240) to a valve plug (280) and, more particularly, apparatus to connect a threaded valve stem to a valve plug of a control valve are disclosed. An example apparatus includes a threaded valve stem (240) received in a threaded opening (282) of a valve plug (280) and a securement member received in an adjacent opening (287) extending from at least one of the threaded opening (282) or an exterior surface (241) of the valve stem (240) to. secure non-rotatably the threaded valve stem (240) to the valve plug(280).