ISO 14085-5:2015 航空宇宙シリーズ—油圧フィルターエレメント—試験方法—パート5：流動疲労に対する耐性 | ページ 2

Foreword

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The committee responsible for this document is ISO/TC 20, Aircraft and space vehicles, Subcommittee SC 10, Aerospace fluid systems and components.

ISO 14085 consists of the following parts, under the general title Aerospace series — Hydraulic Filter elements — Test methods:

• Part 1: Test sequence
• Part 2: Conditioning
• Part 3: Filtration efficiency and retention capacity
• Part 4: Verification of collapse/burst pressure rating
• Part 5: Resistance to flow fatigue
• Part 6: Cleanliness Level

Introduction

In aerospace hydraulic fluid power systems, power is transmitted and controlled through a liquid under pressure. The liquid is both a lubricant and power-transmitting medium. The presence of solid contaminant particles in the liquid interferes with the ability of the hydraulic fluid to lubricate and causes wear and malfunction of the components. The extent of contamination in the fluid has a direct bearing in the performance, reliability, and safety of the system, and needs to be controlled to levels that are considered appropriate for the system concerned.

Different principles are used to control the contamination level of the fluid by removing solid contaminant particles; one of them uses a filter element enclosed in a filter housing. The filter element is the porous device that performs the actual process of filtration. The complete assembly is designated as a filter.

The effectiveness of the filter element in controlling contaminants is dependent on its design and its sensitivity to any dynamic operating conditions that may stress the filter element and cause damage to it, especially as it becomes clogged and the differential pressure rises.

This part of ISO 14085 provides a procedure to determine the ability of a filter element, under increasing differential pressures, to withstand dynamic operating conditions by evaluating its remaining integrity and performance after being subjected to cyclic flow variations.

1 Scope

This part of ISO 14085 specifies a method for determining the resistance of a filter element to flow fatigue caused by varying flow through the filter in various stages of the filter contaminant loading process. The filter is subjected to a uniform varying flow rate for a specified number of cycles, at a number of predetermined differential pressures.

Although the number of cycles and differential pressure conditions used in this part of ISO 14085 is meant to simulate possible service conditions, this part of ISO 14085 is not intended to qualify a filter element under replicate conditions of service; this can only be done by a specific test protocol developed for the purpose, including actual conditions of use, for example the operating fluid, contamination, and exact cyclic flow conditions.

This part of ISO 14085 establishes a method for verifying the ability of a filter element to withstand the stress caused by cyclic differential pressures induced by a variable flow rate.

The test data resulting from application of this part of ISO 14085 can be used to compare the performance of aerospace hydraulic filter elements.

2 Normative references

The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies

3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 5598 and the following apply.