BS ISO 4411-2008 Hydraulic fluid power - Valves - Determination of pressure differential flow characteristics《液压流体动力 阀门 压差 流量特性的测定》.pdf

1、BS ISO 4411:2008ICS 23.100.50NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDHydraulic fluidpower Valves Determination ofpressure differential/flow characteristicsThis British Standardwas published under theauthority of the StandardsPolicy and StrategyCommittee

2、on 31 October2008 BSI 2008ISBN 978 0 580 58646 0Amendments/corrigenda issued since publicationDate CommentsBS ISO 4411:2008National forewordThis British Standard is the UK implementation of ISO 4411:2008.The UK participation in its preparation was entrusted to TechnicalCommittee MCE/18/-/5, Control

3、components.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisionsof a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immun

4、ityfrom legal obligations.BS ISO 4411:2008Reference numberISO 4411:2008(E)ISO 2008INTERNATIONAL STANDARD ISO4411Second edition2008-10-01Hydraulic fluid power Valves Determination of pressure differential/flow characteristics Transmissions hydrauliques Distributeurs Dtermination des caractristiques d

5、e pression diffrentielle/dbit BS ISO 4411:2008ISO 4411:2008(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobes 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

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8、form 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, witho

9、ut permission in writing from either ISO at the address below or ISOs 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 righ

10、ts reservedBS ISO 4411:2008ISO 4411:2008(E) ISO 2008 All rights reserved iiiForeword 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

11、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 clo

12、sely 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. Dra

13、ft 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 docu

14、ment may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 4411 was prepared by Technical Committee ISO/TC 131, Fluid power systems, Subcommittee SC 5, Control products and components. This second edition cancels and replaces the fi

15、rst edition (ISO 4411:1986), which has been technically revised. BS ISO 4411:2008ISO 4411:2008(E) iv ISO 2008 All rights reservedIntroduction In hydraulic fluid power systems, power is transmitted and controlled through a liquid under pressure within an enclosed circuit. Hydraulic valves control the

16、 direction, pressure or flow rate of the fluid in the system. When fluid flows through a valve, it encounters some resistance, which results in a loss of pressure; this loss is called the pressure differential. This International Standard is intended to unify testing methods for hydraulic fluid powe

17、r valves to enable the pressure differential/flow characteristics of different valves to be compared. BS ISO 4411:2008INTERNATIONAL STANDARD ISO 4411:2008(E) ISO 2008 All rights reserved 1Hydraulic fluid power Valves Determination of pressure differential/flow characteristics 1 Scope This Internatio

18、nal Standard specifies methods for determining, under steady-state conditions, the pressure differential caused by the flow through any given path in a hydraulic fluid power valve. Requirements for test installations, procedures and presentation of results are specified. 2 Normative references The f

19、ollowing 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 1219-1, Fluid power systems and components Graphic

20、 symbols and circuit diagrams Part 1: Graphic symbols for conventional use and data-processing applications ISO 4401, Hydraulic fluid power Four-port directional control valves Mounting surfaces ISO 55981), Fluid power systems and components Vocabulary ISO 5781, Hydraulic fluid power Pressure-reduci

21、ng valves, sequence valves, unloading valves, throttle valves and check valves Mounting surfaces ISO 6263, Hydraulic fluid power Compensated flow-control valves Mounting surfaces ISO 6264, Hydraulic fluid power Pressure-relief valves Mounting surfaces ISO 9110-1, Hydraulic fluid power Measurement te

22、chniques Part 1: General measurement principles ISO 9110-2, Hydraulic fluid power Measurement techniques Part 2: Measurement of average steady-state pressure in a closed conduit ISO 10372, Hydraulic fluid power Four- and five-port servovalves Mounting surfaces 3 Terms and definitions For the purpose

23、s of this document, the terms and definitions given in ISO 5598 and the following apply. 3.1 tare pressure differential pressure loss between the pressure-tapping points as generated by the test equipment exclusive of the test valve 1) To be published. (Revision of ISO 5598:1985) BS ISO 4411:2008ISO

24、 4411:2008(E) 2 ISO 2008 All rights reserved3.2 measured pressure differential measured pressure loss between the pressure-tapping points, including the pressure loss through the test valve and the test equipment 3.3 flow rate qVvolume rate of flow at the point of measurement 3.4 pressure differenti

25、al p pressure loss attributed to the test valve 4 Symbols and units 4.1 The symbols and units used throughout this International Standard are shown in Table 1. 4.2 The graphical symbols used in Figures 1 to 3 are in accordance with ISO 1219-1. Table 1 Symbols and units Reference subclause Quantity S

26、ymbol DimensionaUnitb3.3 3.4 Volume flow rate Pressure differential Inside diameter of tube Temperature Kinematic viscosity Mass density qVp d L3T1ML1T2L L2T1ML3m3/s Pacm C m2/s kg/m3aM signifies mass, L signifies length, T signifies time. bThe use of practical units for the presentation of results

27、is described in Annex A. c1 Pa = 1 N/m2. 5 Test installations NOTE Annex B provides a checklist for the selection of appropriate items upon which agreement between the parties concerned is recommended prior to testing. 5.1 Selection, calibration and installation of equipment 5.1.1 Equipment shall be

28、 selected in accordance with ISO 9110-2. 5.1.2 Calibration shall be carried out in accordance with ISO 9110-1. 5.1.3 The test set-up shall be in accordance with ISO 9110-2. BS ISO 4411:2008ISO 4411:2008(E) ISO 2008 All rights reserved 35.2 Test circuit 5.2.1 A circuit suitable for testing valves as

29、shown in Figure 1 shall be used. The requirements for the position of the pressure-measuring connections and the flow meter shown in Figure 1 and referred to in 5.2.5 through 5.2.9 apply only to Class A measurement accuracy. Figure 1 illustrates a basic circuit that does not incorporate all the safe

30、ty devices necessary to protect against damage in the event of component failure. It is important that those responsible for carrying out the test give due consideration to safeguarding both personnel and equipment. Key 1 controllable flow supply, at controlled fluid temperature 2 relief valve (circ

31、uit protection) 3 stop valve (normally fully open) 4 pressure differential measuring device 5 test valve 6 temperature measuring device 7 flow meter Figure 1 Test circuit diagram BS ISO 4411:2008ISO 4411:2008(E) 4 ISO 2008 All rights reserved5.2.2 On subplate-mounted valves and sandwich-mounted valv

32、es, measurements should be carried out using standard pressure-tapping plates (intermediate plates) as shown in Figure 2. In this case, the requirements given in 5.2.5 through 5.2.8 and 5.3 do not apply. Dimension A shall be the maximum port size specified in ISO 4401, ISO 5781, ISO 6263, ISO 6264 o

33、r ISO 10372 for the valve being tested. Dimension B shall be appropriate for the selected interface O-ring. The threaded port size shall be appropriate for the flow rating of the valve. Only one port is shown, which would be typical for P, T, A and B ports. Dimensions in millimetres Figure 2 Standar

34、d pressure-tapping plate for subplate-mounted valves 5.2.3 A fluid supply with controllable flow shall be used. 5.2.4 A relief valve shall be installed to protect the circuit from excessive pressure. 5.2.5 To establish a steady flow pattern at the upstream tapping, a visibly straight, uniform-bore t

35、ube length of at least 10d shall be used. 5.2.6 A visibly straight, uniform-bore tube length of at least 5d shall be used between the upstream and downstream pressure tapping and the valve. 5.2.7 To ensure adequate pressure recovery, a visibly straight, uniform-bore tube length of at least 10d shall

36、 be used between the test valve and the downstream pressure tapping. 5.2.8 A visibly straight, uniform-bore tube length of at least 5d shall be used between the downstream pressure tapping and the temperature measuring point. 5.2.9 A flow meter shall be installed to measure the flow rate at a point

37、at least 5d downstream of the tube length described in 5.2.8. Turbines or thermal meters that do not contain flow straighteners should be installed at least 10d downstream. BS ISO 4411:2008ISO 4411:2008(E) ISO 2008 All rights reserved 55.2.10 Tubes and connectors consistent with the port size of the

38、 valve shall be used. 5.3 Pressure-tapping points 5.3.1 Static pressure measuring connections shall be used in accordance with ISO 9110-2. 5.3.2 For all classes of measurement accuracy, single pressure tapping shall be used. 5.3.3 Tapping shall not be installed on the lowest point of the tube. 6 Tes

39、t procedures 6.1 Measurement accuracy The test shall be carried out to one of three classes of measurement, A, B or C, as defined in ISO 9110-1. The measurement class shall be as agreed between the parties concerned. Permissible systematic errors for the measurement classes shall be as shown in Tabl

40、e 2. Table 2 Permissible systematic errors of measuring instruments as determined during calibration Permissible systematic errors for classes of measurement accuracy Parameter of measuring instrument A B C Flow rate, q, expressed in percent 1,0 2,0 3,0 Differential pressure, p, expressed in percent

41、 1,0 3,0 5,0 Temperature, expressed in kelvins 0,5 1,0 2,0 6.2 Test fluid 6.2.1 A test fluid approved by the manufacturer of the valve shall be used when carrying out the tests. A description of the fluid shall be recorded, and its mass density, , and kinematic viscosity, , for the range of temperat

42、ure used in the test shall be stated. 6.2.2 The fluid cleanliness level shall be maintained within the limits recommended by the valve manufacturer. 6.2.3 For class A or B measurement accuracy, the mass density, , and the kinematic viscosity, , from fluid samples taken from the test installation sha

43、ll be measured immediately before the test. 6.2.4 For class C measurement accuracy, it is permissible to use density and viscosity data obtained from the fluid supplier. 6.3 Temperatures 6.3.1 The fluid temperature shall be controlled during the test within the limits specified in Table 3. Table 3 P

44、ermissible variation in indicated fluid temperature Class of measurement accuracy A B C Variation in temperature indication, expressed in kelvins 1,0 2,0 4,0 BS ISO 4411:2008ISO 4411:2008(E) 6 ISO 2008 All rights reserved6.3.2 The test shall be carried out within the range of fluid temperatures reco

45、mmended by the valve manufacturer for the intended application of the valve. 6.4 Steady-state conditions 6.4.1 All readings shall only be recorded after steady-state conditions have been reached. 6.4.2 When steady-state conditions are reached for a specific test condition, only one set of readings o

46、f individual quantities shall be taken over concurrent common time periods. Each reading shall be recorded as the mean value of each quantity being measured. 6.5 Procedure 6.5.1 Install the test valve in the test circuit using the upstream and downstream ports in the valve or in the tapping plate as

47、 required. 6.5.2 Set the valve control for the flow path (or flow rate) required, if applicable. 6.5.3 The number of sets of readings to be taken and their distribution over the range shall be selected to give a representative indication of the performance of the valve over the full range of flow se

48、lected for the test. 6.5.4 For each flow selected in 6.5.3, measure the upstream pressure and the downstream pressure. If the test valve is a subplate-mounted type, skip 6.5.5 and 6.5.6. 6.5.5 If the test valve is a line-mounted type, remove it from the test circuit and connect the lines as specifie

49、d in 6.5.1 to complete the test circuit without the test valve. This step is not necessary when a test circuit in accordance with 5.2.2 is used. 6.5.6 Repeat the pressure measurements of 6.5.4. 6.6 Pressure differential calculation 6.6.1 Where appropriate, correct each pressure reading for pressure head effects in accordance with ISO 9110-2. 6.6.2 Calculate the measured pressure differential for each reading in 6.5.4 by subtracting t