ISO-21018-1-2008.pdf

Reference number ISO 21018-1:2008(E) © ISO 2008 INTERNATIONAL STANDARD ISO 21018-1 First edition 2008-04-15 Hydraulic fluid power Monitoring the level of particulate contamination of the fluid Part 1: General principles Transmissions hydrauliques Surveillance du niveau de pollution particulaire des fluides Partie 1: Principes généraux Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Boeing Co/5910770001 Not for Resale, 07/25/2008 04:00:42 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 21018-1:2008(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat accepts no liability in this area. Adobe is a trademark of Adobe Systems Incorporated. Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below. COPYRIGHT PROTECTED DOCUMENT © ISO 2008 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISO's member body in the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii © ISO 2008 All rights reserved Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Boeing Co/5910770001 Not for Resale, 07/25/2008 04:00:42 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 21018-1:2008(E) © ISO 2008 All rights reserved iii Contents Page Foreword iv Introduction v 1 Scope . 1 2 Normative references. 1 3 Terms and definitions. 2 4 Health and safety 3 4.1 General. 3 4.2 Electric power . 3 4.3 Mechanical fluid power 4 4.4 Process liquids . 4 5 Selection of monitoring technique 4 5.1 General. 4 5.2 Selection 5 6 Procedures and precautions . 5 6.1 General. 5 6.2 Obtaining representative samples 5 6.3 Off-line sampling. 5 6.4 On-line analysis 6 6.5 In-line analysis 6 6.6 Suction (sip) analysis from reservoirs or containers . 6 6.7 Calibration procedures. 7 6.8 Checking data validity 7 6.9 Training 7 6.10 Controlling the precision of the technique 8 7 Test report . 8 Annex A (informative) Summary of various technique attributes. 9 Annex B (informative) Description and relative merits of different contaminant monitoring techniques. 15 Bibliography. 24 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Boeing Co/5910770001 Not for Resale, 07/25/2008 04:00:42 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 21018-1:2008(E) iv © ISO 2008 All rights reserved Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 21018-1 was prepared by Technical Committee ISO/TC 131, Fluid power systems, Subcommittee SC 6, Contamination control. ISO 21018 consists of the following parts, under the general title Hydraulic fluid power Monitoring the level of particulate contamination of the fluid: Part 1: General principles Part 3: Use of the filter blockage technique A Part 2, dealing with the calibration and verification procedure for field contamination monitoring, and a Part 4, dealing with the use of the light extinction technique, are under development. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Boeing Co/5910770001 Not for Resale, 07/25/2008 04:00:42 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 21018-1:2008(E) © ISO 2008 All rights reserved v Introduction In hydraulic fluid power systems, power is transmitted through a liquid under pressure within a closed circuit. The liquid is both a lubricant and power-transmitting medium. The presence of solid particulate contamination in the liquid interferes with the ability of the hydraulic liquid to lubricate and causes wear to the components. The extent of this form of contamination in the liquid has a direct bearing on the performance and reliability of the system and it is necessary that this be controlled to levels that are considered appropriate for the system concerned. Hydraulic filters are used to control the amount of particulate contamination to a level that is suitable for both the contaminant sensitivity of the system and the level of reliability required by the user. Operators of hydraulic equipment are gradually defining maximum particle concentration levels for components, systems and processes, beyond which corrective actions are implemented to normalize the levels. These are often referred to as the required cleanliness level (RCL). The cleanliness level is obtained by sampling the hydraulic liquid and measuring the particulate contamination level. If the level is above the RCL, then corrective actions are necessary to restore the situation. To avoid taking unnecessary actions, which can often prove costly, precision in sampling and measuring the particulate contamination level is required. A comprehensive range of measurement equipment is available, but the instruments used are usually laboratory-based. This often requires that the equipment is operated in a special environment by specialist laboratories and this delays delivery of the test result to the user. To overcome this disadvantage, instruments are being continuously developed to determine the particulate contamination level, either using equipment that can be operated in or near the workplace or directly using on-line or in-line techniques. For equipment operated in the workplace, direct traceability to national measurement standards might not be appropriate, or relevant, and the instruments are used to monitor the general level of particulate contamination or to inform the user of a significant change in the level. When a significant change in the particulate contamination level is detected, the actual level is then usually qualified by using an approved particle-counting method. Also, these monitors can have simplified circuitry compared to similar laboratory units and this means that they are not so precise. In addition, some instruments are designed to work on the “go/no-go” principle and their ability to rapidly evaluate the cleanliness level has resulted in an increase in their usage both in the fluid power industry and other markets. Unfortunately, the lack of a standardized method for their use, recalibration (if applicable) and means of checking the output validity means that the variability in the measurement data is at a level higher than is desirable. This International Standard has been developed to provide uniform and consistent procedures for instruments that are used for monitoring the contamination levels in hydraulic systems, especially those where direct traceability to national measurement standards is not possible or is not applicable. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Boeing Co/5910770001 Not for Resale, 07/25/2008 04:00:42 MDTNo reproduction or networking permitted without license from IHS -,-,- Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Boeing Co/5910770001 Not for Resale, 07/25/2008 04:00:42 MDTNo reproduction or networking permitted without license from IHS -,-,- INTERNATIONAL STANDARD ISO 21018-1:2008(E) © ISO 2008 All rights reserved 1 Hydraulic fluid power Monitoring the level of particulate contamination of the fluid Part 1: General principles 1 Scope This part of ISO 21018 specifies methods and techniques that are applicable to the monitoring of particulate contamination levels in hydraulic systems. It also describes the relative merits of various techniques so that the correct monitor for a given application can be selected. The techniques described in this part of ISO 21018 are suitable for monitoring a) the general cleanliness level in hydraulic systems, b) the progress in flushing operations, c) support equipment and test rigs. This part of ISO 21018 can also be applicable for other liquids (e.g. lubricants, fuels and process liquids). NOTE Instruments used to monitor particulate contamination are not considered as or claimed to be particle counters, even if they use the same physical principles as particle counters. 2 Normative references The following referenced documents are indispensable for the application 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. ISO 3722, Hydraulic fluid power Fluid sample containers Qualifying and controlling cleaning methods ISO 4021, Hydraulic fluid power Particulate contamination analysis Extraction of fluid samples from lines of an operating system ISO 4406:1999, Hydraulic fluid power Fluids Method for coding the level of contamination by solid particles ISO 5598, Fluid power systems and components Vocabulary ISO 11171, Hydraulic fluid power Calibration of automatic particle counters for liquids ISO 11500:1997, Hydraulic fluid power Determination of particulate contamination by automatic counting using the light extinction principle ISO 11943, Hydraulic fluid power On-line automatic particle-counting systems for liquids Methods of calibration and validation ISO 12103-1:1997, Road vehicles Test dust for filter evaluation Part 1: Arizona test dust Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Boeing Co/5910770001 Not for Resale, 07/25/2008 04:00:42 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 21018-1:2008(E) 2 © ISO 2008 All rights reserved 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 5598 and the following apply. 3.1 automatic particle counter APC instrument that automatically counts and sizes individual particles suspended in a liquid using the light extinction principle 3.2 coincidence detection of two or more particles as a single particle NOTE Adapted from ISO 11500:1997, definition 3.2. 3.3 dynamic range ratio of the largest and smallest particle size that a sensor can analyse 3.4 filter medium fabric of the filter that removes and retains particles 3.5 gel shapeless material that lacks definition and can interfere with the counting or monitoring process NOTE Gels are usually formed by chemical reaction with the hydraulic liquid. 3.6 in-line analysis analysis of a fluid sample of the liquid by an instrument that is permanently connected to a working flow line and where all of the liquid in that line passes through the sensor 3.7 off-line analysis analysis of a fluid sample by an instrument that is not directly connected to the hydraulic system 3.8 on-line analysis analysis performed on a fluid supplied directly to the instrument by a continuous line from the hydraulic system NOTE The instrument can be either permanently connected to the flow line or connected prior to analysis. 3.9 mesh type of filter medium that is made by weaving strands of wire or material filaments 3.10 particle size characteristic dimension of a particle that defines the magnitude of the particle in terms of a physically measurable dimension related to the analysis technique used, such as the longest dimension or the equivalent spherical diameter and shall be stated in each standard 3.11 pore size size of hole in the filter medium as stated by the instrument manufacturer Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Boeing Co/5910770001 Not for Resale, 07/25/2008 04:00:42 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 21018-1:2008(E) © ISO 2008 All rights reserved 3 3.12 qualitative data data that have less precision or accuracy than quantitative methods and usually gives results in ranges rather than exact numbers 3.13 quantitative data data in the form of an exact numerical value of a parameter 3.14 required cleanliness level RCL liquid cleanliness level specified for a system or process 3.15 sampler device for extracting a representative sample from a larger source 3.16 silt very small particles ( 20/18/15 (see ISO 4406:1999). d) Typical analysis time is 5 min. B.2.3 Limitations The following key limitations have been identified. a) It requires a high concentration of particles for accurate detection 19/17/14 (see ISO 4406:1999). b) The particle size distribution is based upon particle volume. c) It is not generally used in the fluid power ind