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1、1 Date: 29 August 2007 Origin: National Latest date for receipt of comments: 31 OCTOBER 2007 Project no.: 2005/01221 Responsible committee: IS/NFE/4/1/2 Torque measurement and testing Interested committees: Title: Draft BS 7882 Method for calibration and classification of torque measuring devices Su
2、persession information: If this document is published as a standard, the UK implementation of it will supersede BS7882:1997. If you are aware of a current national standard which may be affected, please notify the secretary (contact details below). WARNING: THIS IS A DRAFT AND MUST NOT BE REGARDED O
3、R USED AS A BRITISH STANDARD. THIS DRAFT IS NOT CURRENT BEYOND 31 OCTOBER 2007. This draft is issued to allow comments from interested parties; all comments will be given consideration prior to publication. No acknowledgement will normally be sent. See overleaf for information on commenting. No copy
4、ing is allowed, in any form, without prior written permission from BSI except as permitted under the Copyright, Designs and Patent Act 1988 or for circulation within a nominating organization for briefing purposes. Electronic circulation is limited to dissemination by e-mail within such an organizat
5、ion by committee members. Further copies of this draft may be purchased from BSI Customer Services, Tel: +44(0) 20 8996 9001 or email ordersbsi-. British, International and foreign standards are also available from BSI Customer Services. British Standards on CD or Online are available from British S
6、tandards Publishing Sales Limited. Tel: 01344 404409 or email bsonlinetechindex.co.uk. Information on the co-operating organizations represented on the committees referenced above may be obtained from the responsible committee secretary. Cross-references The British Standards which implement Interna
7、tional or European publications referred to in this draft may be found via the British Standards Online Service on the BSI web site http:/www.bsi- . Direct tel: 020 8996 7261 Responsible Committee Secretary: Mr A Price (BSI) E-mail: alex.pricebsi- Draft for Public Comment Head Office 389 Chiswick Hi
8、gh Road London W4 4AL Telephone: +44(0)20 8996 9000 Fax: +44(0)20 8996 7001 www.bsi- Form 36 DPC: 07/30133498 DC Licensed Copy: London South Bank University, London South Bank University, Fri Oct 05 02:27:12 GMT+00:00 2007, Uncontrolled Copy, (c) BSI 2 Introduction Your comments on this draft are we
9、lcome and will assist in the preparation of the consequent British Standard. If no comments are received to the contrary, this draft may be implemented unchanged as a British Standard. Submission The guidance given below is intended to ensure that all comments receive efficient and appropriate atten
10、tion by the responsible BSI committee. Annotated drafts are not acceptable and will be rejected. All comments must be submitted, preferably electronically, to the Responsible Committee Secretary at the address given on the front cover. Comments should be compatible with Version 2003 of Microsoft Wor
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13、1) Paragraph/ Figure/Table/N ote (e.g. Table 1) Type of com- ment Comment (justification for change) by the MB Proposed change by the MB Secretariat observations on each comment submitted 3.1 Definition 1 ed Definition is ambiguous and needs clarifying. Amend to read . so that the mains connector to
14、 which no connection . 6.4 Paragraph 2 te The use of the UV photometer as an alternative cannot be supported as serious problems have been encountered in its use in the UK. Delete reference to UV photometer. Microsoft and MS-DOS are registered trademarks, and Windows is a trademark of Microsoft Corp
15、oration. Licensed Copy: London South Bank University, London South Bank University, Fri Oct 05 02:27:12 GMT+00:00 2007, Uncontrolled Copy, (c) BSI BS 7882:2007 3 Method for Calibration and classification of torque measuring devices Licensed Copy: London South Bank University, London South Bank Unive
16、rsity, Fri Oct 05 02:27:12 GMT+00:00 2007, Uncontrolled Copy, (c) BSI BS 7882:2007 4 Contents Foreword 5 1 Scope 6 2 Terms, definitions, abbreviations and symbols 6 3 Preparation for calibration 9 4 Calibration procedure 13 5 Calculation of results 14 6 Classification of torque measuring devices 17
17、7 Calibration certificate 18 Annexes Annex A (informative) 20 Orientation diagrams 20 Annex B (informative) 22 Method example of determining uncertainty of the calibration results of the torque measuring device 22 List of figures Figure A.1 Example of preloading and calibration sequences for a torqu
18、e transducer with round shaft drives, six increasing and decreasing torques, classes 0.05 to 5.0 20 Figure A.2 Example of preloading and calibration sequences for a torque transducer with round shaft drives, six increasing torques only, classes 0.05 to 5.0 20 Figure A.3 Example of preloading and cal
19、ibration sequences for a torque transducer with square drives, six increasing and decreasing torques, classes 0.05 to 5.0 20 Figure A.4 Example of preloading and calibration sequences for a torque transducer with square drives, six increasing torques only, classes 0.05 to 5.0 21 Figure A.5 Example o
20、f preloading and calibration sequences for a torque transducer, six increasing and decreasing torques, classes 0.2 to 5.0. 21 Figure A.6 Example of preloading and calibration sequences for a torque transducer, six increasing torques only, classes 0.2 to 5.0 21 List of tables Table 1 Uncertainty of c
21、alibration torques 9 Table 2 Criteria for classification of torque measuring devices 18 Licensed Copy: London South Bank University, London South Bank University, Fri Oct 05 02:27:12 GMT+00:00 2007, Uncontrolled Copy, (c) BSI BS 7882:2007 5 Foreword This British Standard is published by BSI and came
22、 into effect on XX Month 200X.It was prepared by Technical Committee ISE/NFE/4, Torque measurement and testing. A list of organizations represented on this committee can be obtained on request to its secretary. Supersession BS 7882:2007 supersedes BS 7861-1:1996, which is withdrawn. Presentational c
23、onventions The provisions of this standard are presented in roman (i.e. upright) type. Its requirements are expressed in sentences in which the principal auxiliary verb is “shall”. Commentary, explanation and general informative material is presented in smaller italic type, and does not constitute a
24、 normative element. Contractual and legal considerations This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard cannot confer immunity from legal obligations. Licensed Copy: London
25、 South Bank University, London South Bank University, Fri Oct 05 02:27:12 GMT+00:00 2007, Uncontrolled Copy, (c) BSI BS 7882:2007 6 1 Scope This British Standard specifies the requirements for the calibration and classification of torque measuring devices including those used for the calibration of
26、hand torque tools to BS EN ISO 6789. It describes the method of calibration, calculation of calibration results and the classification of the torque measuring device in a static mode. The information to be given on the certificate of calibration is also listed. 2 Terms, definitions, abbreviations an
27、d symbols For the purposes of this British Standard, the following terms, definitions, abbreviations and symbols apply. NOTE Where applicable, this British Standard has been prepared using PD 6461-1. 2.1 torque product of tangential force and length applied about a known centre of rotation 2.2 torqu
28、e measuring device system comprising of an electrical, mechanical, hydraulic or optical torque transducer, with associated instrumentation, including the automated logging of data when part of the device NOTE The instrumentation can be an electronic instrument, a mechanical device, i.e. a scale and
29、pointer system, or a Bourdon tube instrument. 2.3 reference standard equipment used to generate or to measure the reference torque applied to the torque measuring device that is being calibrated NOTE Torques may be generated by a power source monitored by the reference standard. 2.4 calibration torq
30、ue torque, with traceability derived from national standards of mass, length and time and of specified uncertainty of measurement, which can be applied to the torque measuring device 2.5 resolution r smallest discernable measurement interval on the torque measuring device indicator Licensed Copy: Lo
31、ndon South Bank University, London South Bank University, Fri Oct 05 02:27:12 GMT+00:00 2007, Uncontrolled Copy, (c) BSI BS 7882:2007 7 2.6 lower limit of calibration Tmin lower value of torque at which a torque measuring device of a given class can be calibrated 2.7 relative repeatability R1 closen
32、ess of the agreement between the results of two successive measurements from the same applied torque, carried out under the same conditions of measurement 2.8 relative reproducibility R2 closeness of agreement between the results of successive measurements from the same applied torque, carried out u
33、nder changed conditions of measurement 2.9 deflection d algebraic difference between the indicator reading prior to the application of a torque and the indicator reading for each applied torque in a given measurement series NOTE The deflection may be derived from either digital data output or visual
34、 data output. 2.10 residual deflection d0 algebraic difference between the indicator readings before and after the application of a single series of torques 2.11 relative error of interpolation Eit difference between the value of the mean deflection for a given value of increasing torque and the cor
35、responding calculated value of deflection for the given torque, obtained from a mathematically fitted curve NOTE For the purposes of this standard, relative error of interpolation is expressed as a percentage of the computed deflection for the given increasing torque. Licensed Copy: London South Ban
36、k University, London South Bank University, Fri Oct 05 02:27:12 GMT+00:00 2007, Uncontrolled Copy, (c) BSI BS 7882:2007 8 2.12 relative residual deflection R0 maximum residual deflection obtained from all the series of torques NOTE For the purposes of this standard, relative residual deflection is e
37、xpressed as a percentage of the mean deflection for the maximum torque applied. 2.13 relative reversibility R3 difference between the deflection obtained from the last given torque series applied in an increasing mode and the deflection obtained from the same given torque applied in a decreasing mod
38、e NOTE For the purposes of this standard, relative reversibility is expressed as a percentage of the deflection of the last series for the given torque, applied in an increasing mode. 2.14 relative error of indication Ei mean deflection for a given value of increasing torque minus the corresponding
39、value of applied torque NOTE 1 For the purposes of this standard, relative error of indication is expressed as a percentage of applied torque. NOTE 2 Relative error of indication is only used where the deflection is in units of torque. 2.15 loading direction direction of applied torque, either clock
40、wise or anti-clockwise about the axis of rotation, when viewed from the end of the torque measuring device to which the calibration torque is applied 2.16 data acquisition system electronic module that has the ability to transfer, store, amplify and filter signals from a transducer NOTE Where analog
41、ue signals are acquired by the transducer, these are converted into a digital data stream using an analogue to digital converter. The stream of data may be digitally filtered, re-sampled and stored, or logged ready for analysis. Licensed Copy: London South Bank University, London South Bank Universi
42、ty, Fri Oct 05 02:27:12 GMT+00:00 2007, Uncontrolled Copy, (c) BSI BS 7882:2007 9 3 Preparation for calibration 3.1 Reference standard 3.1.1 Calibration torques 3.1.1.1 Uncertainty of calibration torques Values for the maximum permissible uncertainty of the calibration torques applied for the determ
43、ination of different classifications of the torque measuring device shall not exceed the values given in Table 1. Where a reference standard is used to determine a calibration torque, it shall conform to Table 1. Table 1 Uncertainty of calibration torques Class of torque measuring device to be calib
44、rated Maximum permissible uncertainty of calibration torque applieda % 0.05 0.01 0.1 0.02 0.2 0.04 0.5 0.10 1.0 0.20 2.0 0.40 5.0 1.00 a Using a coverage factor of k = 2 to give a confidence level of approximately 95%. 3.1.1.2 Traceability of measurements All definitive measurements, such as mass, l
45、ength, time, temperature, etc., shall be traceable to national standards; evidence of this shall be provided by a certificate of calibration. 3.2 Condition and identification of a torque measuring device 3.2.1 Calibration shall not be commenced unless the torque measuring device is considered to be
46、in good working order and is identified with a serial number. The maximum working torque shall first have been established. NOTE Good working order includes the drive components being of a sufficiently good fit to exert a minimum bias on the system. 3.2.2 All parts of the torque measuring device sha
47、ll be identified in accordance with 3.2.1, including the following, where applicable: a) signal cables; b) switch boxes; c) interfaces; d) data acquisition systems; e) computers and software where they are part of the torque measuring device. Licensed Copy: London South Bank University, London South
48、 Bank University, Fri Oct 05 02:27:12 GMT+00:00 2007, Uncontrolled Copy, (c) BSI BS 7882:2007 10 3.2.3 Where an electrical indicator used with a torque measuring device is replaced with another, the following requirements shall be met to ensure that the calibration is not invalidated. a) The origina
49、l indicator shall have a valid calibration certificate, traceable to national standards, that gives the results of a calibration made in terms of the units to be measured. The indicator shall have been calibrated over a range equal to or greater than the range over which it is used with the torque measuring device. b) The replacement indicator shall have a resolution equal to or better than the indicator it is replacing and should have a vali