ISO 14085-4:2015 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4：崩壊/破裂圧力定格の検証 | 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.

Filters are used to control the contamination level of the fluid by removing solid contaminant particles, typically consisting of 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.

As a filter element removes contaminant due to its efficiency, the filter element clogs and its differential pressure increases to values which can affect its structural integrity. The capability of the filter element to maintain a specified fluid cleanliness level depends on its performance and structural integrity, which can both be affected if the filter element differential pressure becomes too high.

A collapse/burst test quantifies the resistance of the filter element to high differential pressures that can occur both due to filter clogging, as well as that occurring in non-steady state operating conditions such as cold starts and decompression surges.

This part of ISO 14085 provides a procedure to verify that a filter element can withstand a designated high differential pressure without failure.

1 Scope

This part of ISO 14085 describes a method for verifying the collapse/burst pressure rating of an aerospace hydraulic fluid power filter element. This represents the capability of a filter element to withstand a designated differential pressure in the normal (intended) direction of flow, created by flowing contaminated fluid through the filter element until either collapse/burst occurs or the maximum expected differential pressure is reached without element failure.

The collapse/burst pressure test can be conducted in conjunction with an efficiency test performed according to the procedure defined in the ISO 14085-3 by continuing the contaminant injection until the designated filter element differential pressure is reached.

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 or contamination.

The tests 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.

Bibliography