Press-Fit Seal Insert Structure for Low-Stiction Hydraulic Valves
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Solution Overview
Problem
Hydraulic valves and regulators face issues with stiction, wear, and corrosion, leading to inefficiencies and high maintenance costs, particularly in subsea environments, due to the static friction between stationary surfaces and the limitations of carbide and stainless steel materials.
Innovation Solution
The use of non-ferrous single crystal materials like sapphire or ruby, or carbide materials, as inserts in hydraulic components, with a press fit connection and a conformable intermediary, reduces friction and wear, allowing for lower energy consumption and improved sealing alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If carbide or stainless steel materials are used for sliding surfaces in hydraulic valves, then wear resistance is improved, but stiction increases causing energy loss and operational issues
Solution Approach 1:
The patent applies composite materials by combining a carbide insert (providing wear resistance) with a stainless steel sleeve (providing ductility and reduced stiction). This composite structure allows the sliding surface to benefit from both materials: the carbide layer resists wear while the stainless steel substrate reduces static friction and allows for deformation to accommodate misalignment, thereby reducing energy loss due to stiction.
2Loss of energy
If carbide inserts are used to reduce stiction, then energy consumption is reduced, but the inserts are brittle and prone to breakage
Solution Approach 1:
The carbide insert is combined with a ductile stainless steel sleeve, creating a composite structure where the stainless steel provides toughness and resistance to breakage, while the carbide layer maintains low friction and reduced energy consumption. The stainless steel substrate absorbs impacts and prevents catastrophic failure of the brittle carbide material.
Solution Approach 2:
The stainless steel sleeve acts as a cushioning layer between the brittle carbide insert and the hydraulic circuit components. This cushioning effect protects the carbide insert from sudden impacts and thermal shocks that could cause breakage, while still allowing the carbide surface to provide low-friction operation.
3Strength
If carbide components are used, then wear resistance is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The sliding surface is segmented into two distinct components: a carbide insert providing wear resistance and a stainless steel sleeve providing structural support and ease of manufacturing. This segmentation allows each component to be optimized independently - the carbide insert can be manufactured using specialized processes while the stainless steel sleeve can be manufactured using conventional machining, thereby reducing overall manufacturing complexity.
Solution Approach 2:
The carbide insert is nested within the stainless steel sleeve, with the carbide insert fitting into a recess in the sleeve. This nested structure allows the brittle carbide material to be protected and supported by the ductile stainless steel, while enabling the carbide insert to be replaced independently if worn, simplifying maintenance and reducing long-term manufacturing costs.
4Duration of action of stationary object
If sliding surfaces are made from durable materials, then service life is extended, but maintenance costs remain high due to debris generation and locking
Solution Approach 1:
The carbide wear-resistant layer is extracted as a separate insert from the stainless steel sleeve. This extraction allows the carbide insert to be independently replaced when worn, without requiring replacement of the entire valve component. The stainless steel sleeve remains in place, and only the carbide insert needs to be removed and replaced, significantly reducing maintenance costs and complexity.
Solution Approach 2:
The carbide insert is designed as a consumable component that can be discarded when worn and replaced with a new insert. The stainless steel sleeve is recovered and retained in the valve assembly. This approach allows the expensive carbide material to be replaced only when necessary, while the more economical stainless steel component is reused, optimizing maintenance costs.
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 configuration results in lower friction, reduced wear and corrosion, and improved reliability of hydraulic components, with reduced energy requirements and lower maintenance costs, while maintaining effective sealing performance.
Implementation Method 1
The insert is connected to the seal plate or sliding seal assembly by a compressed member disposed between the insert and the adjacent surface of seal plate or sliding seal assembly
Data Source
AI summary
A shear seal includes a seal plate having a first seal surface and a sliding seal assembly having a second seal surface, and at least one of the first and second sealing surfaces comprise an insert comprising a material different than that of the seal plate or the sliding seal connected to the seal plate or sliding seal assembly by a compressed member disposed between the insert and the adjacent surface of seal plate or sliding seal assembly.