EN 61161-2013 en Ultrasonics - Power measurement - Radiation force balances and performance requirements.pdf

1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationUltrasonics Power measurement Radiation force balances and performance requirementsBS EN 61161:2013National forewordThis British Standard is the UK implementation of EN 61161:201

2、3. It is identical to IEC 61161:2013. It supersedes BS EN 61161:2007,which will be withdrawn on 6 March 2016.The UK participation in its preparation was entrusted to Technical Committee EPL/87, Ultrasonics.A list of organizations represented on this committee can be obtained on request to its secret

3、ary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2013Published by BSI Standards Limited 2013 ISBN 978 0 580 71712 3 ICS 17.140.50Compliance with a British Standard cannot

4、confer immunity from legal obligations.This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 May 2013.Amendments issued since publicationDate Text affectedBRITISH STANDARDBS EN 61161:2013EUROPEAN STANDARD EN 61161 NORME EUROPENNE EUROPISCHE NORM

5、 April 2013 CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Management Centre: Avenue Marnix 17, B - 1000 Brussels 2013 CENELEC - All rights of exploitation in any form and by any means r

6、eserved worldwide for CENELEC members. Ref. No. EN 61161:2013 E ICS 17.140.50 Supersedes EN 61161:2007 English version Ultrasonics - Power measurement - Radiation force balances and performance requirements (IEC 61161:2013) Ultrasons - Mesurage de puissance - Balances de forces de rayonnement et exi

7、gences de fonctionnement (CEI 61161:2013) Ultraschall - Leistungsmessung - Schallfeldkraft-Waagen und Anforderungen an ihre Funktionseigenschaften (IEC 61161:2013) This European Standard was approved by CENELEC on 2013-03-06. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulati

8、ons which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CENELEC memb

9、er. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official version

10、s. CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the N

11、etherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. BS EN 61161:2013EN 61161:2013 - 2 - Foreword The text of document 87/520/FDIS, future edition 3 of IEC 61161, prepared by IEC/TC 87 “Ultrasonics“ was submitted to the IEC-CEN

12、ELEC parallel vote and approved by CENELEC as EN 61161:2013. The following dates are fixed: latest date by which the document has to be implemented at national level by publication of an identical national standard or by endorsement (dop) 2013-12-06 latest date by which the national standards confli

13、cting with the document have to be withdrawn (dow) 2016-03-06 This document supersedes EN 61161:2007. EN 61161:2013 includes the following significant technical changes with respect to EN 61161:2007: whereas the second edition tacitly dealt with circular transducers only, the present edition as far

14、as possible deals with both circular and rectangular transducers, Including a number of symbols for rectangular transducers; attention is paid to focused cases and the influence of scanning has been added; the method of calibrating the radiation force balance now depends on whether the set-up is use

15、d as a primary or as secondary measurement tool; Annex B (basic formulae) has been updated and in Annex C the buoyancy change method is mentioned (see also future EN 62555). Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CENELEC

16、and/or CEN shall not be held responsible for identifying any or all such patent rights. Endorsement notice The text of the International Standard IEC 61161:2013 was approved by CENELEC as a European Standard without any modification. In the official version, for Bibliography, the following notes hav

17、e to be added for the standards indicated: IEC 60601-2-5 NOTE Harmonised as EN 60601-2-5. IEC 61157 NOTE Harmonised as EN 61157. IEC 61846:1998 NOTE Harmonised as EN 61846:1998 (not modified). IEC 62127-1 NOTE Harmonised as EN 62127-1. IEC 62127-2 NOTE Harmonised as EN 62127-2. IEC 62127-3 NOTE Harm

18、onised as EN 62127-3. IEC 62555 1)NOTE Harmonised as EN 62555 1). 1)At draft stage. BS EN 61161:2013- 3 - EN 61161:2013 Annex ZA (normative) Normative references to international publications with their corresponding European publications The following documents, in whole or in part, are normatively

19、 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. NOTE When an international publication has been modified by common m

20、odifications, indicated by (mod), the relevant EN/HD applies. Publication Year Title EN/HD Year IEC 61689 - Ultrasonics - Physiotherapy systems - Field specifications and methods of measurement in the frequency range 0,5 MHz to 5 MHz EN 61689 - BS EN 61161:2013 2 61161 IEC:2013 CONTENTS INTRODUCTION

21、 . 6 1 Scope . 7 2 Normative references . 7 3 Terms and definitions . 7 4 List of symbols . 9 5 Requirements for radiation force balances 9 5.1 General . 9 5.2 Target type 10 5.2.1 General . 10 5.2.2 Absorbing target 10 5.2.3 Reflecting target 10 5.3 Target diameter . 11 5.4 Balance/force measuring

22、system . 11 5.5 System tank 11 5.6 Target support structures 11 5.7 Transducer positioning 11 5.8 Anti-streaming foils 11 5.9 Transducer coupling 12 5.10 Calibration . 12 6 Requirements for measuring conditions 12 6.1 Lateral target position 12 6.2 Transducer/target separation . 12 6.3 Water 12 6.4

23、Water contact 13 6.5 Environmental conditions 13 6.6 Thermal drifts 13 7 Measurement uncertainty . 13 7.1 General . 13 7.2 Balance system including target suspension 13 7.3 Linearity and resolution of the balance system 13 7.4 Extrapolation to the moment of switching the ultrasonic transducer . 14 7

24、.5 Target imperfections 14 7.6 Reflecting target geometry 14 7.7 Lateral absorbers in the case of reflecting target measurements . 14 7.8 Target misalignment 14 7.9 Ultrasonic transducer misalignment . 14 7.10 Water temperature 14 7.11 Ultrasonic attenuation and acoustic streaming . 14 7.12 Foil pro

25、perties . 14 7.13 Finite target size 15 7.14 Plane-wave assumption . 15 7.15 Scanning influence 15 7.16 Environmental influences 15 7.17 Excitation voltage measurement 15 7.18 Ultrasonic transducer temperature . 15 BS EN 61161:201361161 IEC:2013 3 7.19 Nonlinearity . 15 7.20 Acceleration due to grav

26、ity 15 7.21 Other sources 16 Annex A (informative) Additional information on various aspects of radiation force measurements 17 Annex B (informative) Basic formulae 30 Annex C (informative) Other methods of ultrasonic power measurement 36 Annex D (informative) Propagation medium and degassing 37 Ann

27、ex E (informative) Radiation force measurement with diverging ultrasonic beams 38 Annex F (informative) Limitations associated with the balance arrangements . 42 Bibliography 46 Figure 1 Section through an absorbing target . 16 Figure 2 Linearity check: balance readout as a function of the input qua

28、ntity . 16 Figure E.1 Piston result (oscillating curve) for P/cF as a function of ka . 39 Figure E.2 P/cF as a function of ka for four different pseudo-trapezoidal amplitude distributions 39 Figure E.3 Ratio of the radiation conductance G as obtained using a convex-conical reflecting target to an ab

29、sorbing target versus the value of ka 29 41 Figure F.1 Arrangement A 42 Figure F.2 Arrangement B, with convex-conical reflecting target 43 Figure F.3 Arrangement B, with absorbing target . 43 Figure F.4 Arrangement C, with absorbing target . 43 Figure F.5 Arrangement E, with absorbing (a) or concave

30、-conical reflecting (b) target . 43 Figure F.6 Arrangement F, with convex-conical reflecting target 44 Figure F.7 Arrangement F with absorbing target . 44 Table F.1 Advantages and disadvantages of different arrangements 45 BS EN 61161:2013 6 61161 IEC:2013 INTRODUCTION A number of measuring methods

31、exist for the determination of the total emitted power of ultrasonic transducers (1, 2, 31, see also Annex C). The purpose of this International Standard is to establish standard methods of measurement of ultrasonic power in liquids in the lower megahertz frequency range based on the measurement of

32、the radiation force using a gravimetric balance. The great advantage of radiation force measurements is that a value for the total radiated power is obtained without the need to integrate field data over the cross-section of the radiated sound beam. This standard identifies the sources of errors and

33、 describes a systematic step-by-step procedure to assess overall measurement uncertainty as well as the precautions that should be undertaken and uncertainties that should be taken into account while performing power measurements. Basic safety requirements for ultrasonic physiotherapy devices are id

34、entified in IEC 60601-2-5 and make reference to IEC 61689, which specifies the need for acoustic power measurements with an uncertainty better than 15 % at a level of confidence of 95 %. Considering the usual degradation of accuracy in the practical application of this standard, reference measuremen

35、t methods need to be established with uncertainties better than 7 %. Ultrasonic diagnostic device declaration requirements including acoustic power are specified in other IEC standards, as for example in IEC 61157. The measurement of acoustic power accurately and repeatably using a radiation force b

36、alance as defined in this standard is influenced by a number of practical problems. As a guide to the user, additional information is provided in Annex A using the same section and clause numbering as the main body. 1Numbers in square brackets refer to the Bibliography. BS EN 61161:201361161 IEC:201

37、3 7 ULTRASONICS POWER MEASUREMENT RADIATION FORCE BALANCES AND PERFORMANCE REQUIREMENTS 1 Scope This International Standard specifies a method of determining the total emitted acoustic power of ultrasonic transducers based on the use of a radiation force balance; establishes general principles for t

38、he use of radiation force balances in which an obstacle (target) intercepts the sound field to be measured; establishes limitations of the radiation force method related to cavitation and temperature rise; establishes quantitative limitations of the radiation force method in relation to diverging an

39、d focused beams; provides information on estimating the acoustic power for diverging and focused beams using the radiation force method; provides information on assessment of overall measurement uncertainties. This International Standard is applicable to: the measurement of ultrasonic power up to 1

40、W based on the use of a radiation force balance in the frequency range from 0,5 MHz to 25 MHz; the measurement of ultrasonic power up to 20 W based on the use of a radiation force balance in the frequency range 0,75 MHz to 5 MHz; the measurement of total ultrasonic power in well-collimated, divergin

41、g and focused ultrasonic fields; the use of radiation force balances of the gravimetric type or force feedback type. (See also Clause A.1) NOTE 1 A focused beam is converging in the pre-focal range and diverging beyond focus. NOTE 2 Ultrasonic power measurement in the high intensity therapeutic ultr

42、asound (HITU) range, i.e. beyond 1 W or 20 W, respectively, is dealt with in the future IEC 62555. 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

43、applies. For undated references, the latest edition of the referenced document (including any amendments) applies. IEC 61689, Ultrasonics Physiotherapy systems Field specifications and methods of measurement in the frequency range 0,5 MHz to 5 MHz 3 Terms and definitions For the purposes of this doc

44、ument, the following terms and definitions apply. BS EN 61161:2013 8 61161 IEC:2013 3.1 acoustic streaming bulk fluid motion initiated by a sound field 3.2 free field sound field in a homogeneous isotropic medium whose boundaries exert a negligible effect on the sound waves SOURCE: IEC 60050-801:199

45、4, definition 801-23-28, modified the term no longer contains “sound” 3.3 output power P time-average ultrasonic power emitted by an ultrasonic transducer into an approximately free field under specified conditions in a specified medium, preferably water Note 1 to entry: Output power is expressed in

46、 watt (W). 3.4 radiation force acoustic radiation force F time-average force acting on a body in a sound field and caused by the sound field, excluding the component due to acoustic streaming; or, more generally: time-average force (excluding the component due to acoustic streaming) in a sound field

47、, appearing at the boundary surface between two media of different acoustic properties, or within a single attenuating medium Note 1 to entry: Radiation force, acoustic radiation force, is expressed in newton (N). 3.5 radiation pressure acoustic radiation pressure radiation force per unit area Note

48、1 to entry: This term is widely used in the literature. However, strictly speaking, the radiation force per unit area is a tensor quantity 4 and it should be referred to as the acoustic radiation stress tensor when a strict scientific terminology is to be used. The integral quantity “acoustic radiat

49、ion force“ is generally preferred in this International Standard. Whenever at some places, the term “acoustic radiation pressure“ appears it is to be understood as the negative value of the normal radiation stress in the direction of the field axis. Note 2 to entry: Radiation pressure, acoustic radiation pressure, is expressed in pascal (Pa). 3.6 target device specially designed to intercept substantially all of the ultrasonic field and to serve as