Servovalve Filter Assembly for Low Pressure-Loss Contaminant Control
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Solution Overview
Problem
Servo valves face blockages due to contaminants in the fluid, which can lead to reliability issues and increased maintenance needs, particularly in the small gaps between the flapper and nozzles of two-stage servo valves.
Innovation Solution
A filter assembly is introduced, comprising a filter body with end caps and a spacer that restricts fluid flow, filtering contaminants from the fluid supply to the first stage of the servo valve, and is designed to minimize pressure reduction and prevent thermal expansion issues through matching materials and configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a particulate filter is installed to filter contaminants in the fluid, then reliability is improved, but pressure loss increases
Solution Approach 1:
The filter assembly is divided into multiple segments including a filter body, first end cap, second end cap, and spacer. This segmentation allows for optimized fluid flow paths that reduce pressure loss while maintaining effective filtration. The divided structure enables the filter to handle higher flow rates with lower pressure drop across the filter element.
Solution Approach 2:
The patent introduces a circumferential flow path around the filter body as an additional dimension for fluid flow. This circumferential passage allows fluid to bypass the central filtration path, reducing the pressure loss through the filter while still capturing contaminants. The multi-dimensional flow approach balances filtration effectiveness with pressure loss reduction.
2Reliability
If the filter assembly restricts fluid flow to filter contaminants, then reliability is improved, but fluid flow is reduced
Solution Approach 1:
The filter assembly segments the fluid flow into multiple paths: central flow through the filter element and circumferential flow around the filter body. This segmentation enables the system to maintain high overall fluid flow while still providing effective filtration through the central path, thus improving productivity without sacrificing reliability.
Solution Approach 2:
The filter assembly performs multiple functions simultaneously: it filters contaminants through the filter element, guides fluid flow through the circumferential passage, and maintains pressure balance. This multi-functionality allows the single component to preserve fluid flow while achieving reliable contamination removal.
3Ease of manufacture
If end caps are pressed onto the filter body to secure the assembly, then ease of manufacture is improved, but thermal expansion issues arise
Solution Approach 1:
The patent selects materials for the filter body and end caps with matched thermal expansion coefficients. This parameter change in material selection ensures that thermal expansion remains stable across temperature variations, preventing assembly distortion while maintaining the easy press-fit manufacturing process. The material parameters are specifically chosen to resolve the thermal stability issue.
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 filter assembly effectively restricts contaminants, enhancing the reliability of the servo valve by minimizing blockages and reducing maintenance needs, while maintaining precise control of fluid flow and pressure.
Implementation Method 1
a flow restrictor configured to restrict fluid flow between the filter body and each of the first and second fluid outlets
Implementation Method 2
designed to minimize pressure reduction and prevent thermal expansion issues through matching materials and configurations
Data Source
Figure 1
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Figure 4~5
AI summary
The present application relates to a filter assembly (30) for a servo valve. The filter assembly (30) has a filter body (40) defining a chamber; a first end cap (50) having a first fluid outlet (55) at a first end of the filter body (40) and a second end cap (51) having a second fluid outlet (57) at a second end of the filter body (40). A flow restrictor (56, 58) restricts fluid flow between the filter body (40) and each of the first and second fluid outlets (55, 57). A spacer (60) in the chamber (43) spaces the first end cap (50) from the second end cap (51).