GB/T 39095-2020 in English
VALIDAerospace—Hydraulic fluid components—Expression of particulate contamintion levels
- Issued on:2020-09-29
- Implemented on:2021-04-01
- File Format:PDF
- Delivery:Via email within 1~3 business days
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《GB/T 39095-2020航空航天 液压流体零部件 颗粒污染度等级的表述》由TC435（全国航空器标准化技术委员会）归口，主管部门为国家标准化管理委员会。
Introduction
Analysis of the core content of the standard
GB/T 39095-2020 establishes a standardized expression system for the particle contamination of aerospace hydraulic components. Its technical points include:
| Key technologies | Implementation requirements | Basis of detection methods |
|---|---|---|
| Wet volume determination | Test method/calculation method error ≤±1% | ISO18413 |
| Particle collection | Full collection to prevent loss | ISO11171 calibration |
| Grade conversion | V/A geometric factor conversion | Appendix A Typical Values |
Cleanliness Code System
The standard innovatively defines the CCC (Component Cleanliness Code):
- Full expression: CCC=(B9/C11/D10/E8/F8)
- Simplified form: When adjacent levels are the same, they can be combined into (../EF8)
- Single level: When all size segments are of the same level, it is abbreviated as (11)
Application Case: Electro-hydraulic Control Valve Inspection
The wet volume of a certain model of electro-hydraulic directional control valve is 3963cm³. After conversion, the inspection data is:
CCC=(B9/C11/D10/EF8)
Indicates that the valve meets the D10 level requirements in the 25-50μm size segment.
Implementation recommendations
- Computer-aided design is preferred to determine the wet volume of complex parts
- The kinematic viscosity of the test fluid should be kept <5mm²/s when collecting particles
- The report should include the 16 core data specified in Appendix B
Technology evolution analysis
This standard extends the ISO11218 fluid cleanliness code to the field of parts for the first time, and solves the problem of quantifying surface contaminants by introducing the concept of wet volume. The main improvements compared with the old version are as follows:
- New special testing requirements for fiber pollutants (＞100μm)
- Clarify the geometric factor conversion formula V/A=0.001-5cm³/cm²
- Standardize the dual-track testing system of microscope and automatic counter
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