ISO 11943:2021 油圧作動油パワー—液体用のオンライン自動粒子カウントシステム—キャリブレーションと検証の方法 | ページ 2

Foreword

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This document was prepared by Technical Committee ISO/TC 131, Fluid power systems, Subcommittee SC 6, Contamination control.

This third edition cancels and replaces the second edition (ISO 11943:2018), which has been technically revised.

The main changes compared to the previous edition are as follows:

• addition of 7 µm and 14 µm to Table C.2.

Introduction

In hydraulic fluid power systems, power is transmitted, and controlled, through a fluid under pressure within an enclosed circuit. The fluid is both a lubricant and a power-transmitting medium.

Reliable system performance requires control of the fluid medium. Qualitative and quantitative determination of particulate contaminant, in the fluid medium, requires precision in obtaining the sample and determining the size and distribution of contaminants.

Automatic particle counters (APC) are an accepted means for determining the size and size distribution of particulate contamination in fluids. Individual instrument accuracy is established through calibration performed with reference primary calibration suspensions or with secondary calibration suspensions.

APCs are being utilized online to eliminate the need for sample containers, to provide increased accuracy, and to provide for a more rapid access to particle count information. A major application of online particle counting is for evaluating filtration efficiency of hydraulic filter elements during a multi-pass test as defined in ISO 16889. Depending upon the type of filter tested and the capabilities of the APC used, it can be necessary to dilute the samples before flowing through the sensor.

This document establishes procedures for validation of equipment for preparation of secondary calibration suspensions and for online counting of particles with or without dilution circuits, and the online calibration of APCs. It defines a procedure to match two or more particle counters with the intention of improving the accuracy of particulate filtration efficiency as shown, for example, in ISO 16889.

1 Scope

This document establishes methods for:

• validating equipment used to prepare secondary calibration suspensions for automatic particle counters;
• performing online secondary calibration of automatic particle counters;
• matching two or more online particle counters, i.e. to count the same number of particles at a given size by two APCs associated online;
• validating online particle counting systems with and without online dilution as used, for example, to measure the filtration efficiency of a hydraulic filter as described in the multi-pass filter test in ISO 16889.

2 Normative references

The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. 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 ISO 11171 apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

Bibliography