IEC 60534-8-4:2015 establishes a method to predict the noise generated in a control valve by liquid flow and the resulting noise level measured downstream of the valve and outside of the pipe. The noise may be generated both by normal turbulence and by liquid cavitation in the valve. Parts of the method are based on fundamental principles of acoustics, fluid mechanics, and mechanics. The method is validated by test data. This third edition cancels and replaces the second edition published 2005. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: a) Hydrodynamic noise is predicted as a function of frequency and b) Elimination of the acoustic power ratio.<\/p>\n
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| 4<\/td>\n | European foreword Endorsement notice <\/td>\n<\/tr>\n | ||||||
| 5<\/td>\n | Annex ZA (normative) Normative references to international publications with their corresponding European publications <\/td>\n<\/tr>\n | ||||||
| 6<\/td>\n | English CONTENTS <\/td>\n<\/tr>\n | ||||||
| 7<\/td>\n | FOREWORD <\/td>\n<\/tr>\n | ||||||
| 9<\/td>\n | INTRODUCTION <\/td>\n<\/tr>\n | ||||||
| 10<\/td>\n | 1 Scope 2 Normative references 3 Terms and definitions <\/td>\n<\/tr>\n | ||||||
| 11<\/td>\n | 4 Symbols <\/td>\n<\/tr>\n | ||||||
| 13<\/td>\n | 5 Preliminary calculations 5.1 Pressures and pressure ratios 5.2 Characteristic presssure ratio xFz Tables Table 1 \u2013 Numerical constants N <\/td>\n<\/tr>\n | ||||||
| 14<\/td>\n | 5.3 Valve style modifier Fd 5.4 Jet diameter Dj 5.5 Jet velocity 5.6 Mechanical power Wm 6 Noise predictions 6.1 Internal sound pressure calculation <\/td>\n<\/tr>\n | ||||||
| 15<\/td>\n | Table 2 \u2013 Typical values of A\u03b7 <\/td>\n<\/tr>\n | ||||||
| 17<\/td>\n | 6.2 Transmission loss Table 3 \u2013 Indexed third octave center frequencies and \u201cA\u201d weighting factors <\/td>\n<\/tr>\n | ||||||
| 18<\/td>\n | 6.3 External sound pressure calculation 7 Multistage trim 7.1 General <\/td>\n<\/tr>\n | ||||||
| 19<\/td>\n | 7.2 Preliminary calculations 7.3 Prediction of noise level 7.3.1 General criteria 7.3.2 Multistage devices (see Figures 1 and 3) <\/td>\n<\/tr>\n | ||||||
| 20<\/td>\n | 7.3.3 Fixed multistage devices with increasing flow areas (see Figure 2) Figures Figure 1 \u2013 Examples of multistage trim in globe and rotary valves <\/td>\n<\/tr>\n | ||||||
| 21<\/td>\n | Figure 2 \u2013 Example of fixed multistage device with increasing flow area Figure 3 \u2013 Example of multistage trim in globe valve <\/td>\n<\/tr>\n | ||||||
| 22<\/td>\n | Figure 4 \u2013 Globe valve (Cage trim, V-port plug) Figure 5 \u2013 Globe valves (parabolic-plug) <\/td>\n<\/tr>\n | ||||||
| 23<\/td>\n | Figure 6 \u2013 Multihole trims Figure 7 \u2013 Eccentric rotary valves <\/td>\n<\/tr>\n | ||||||
| 24<\/td>\n | Figure 8 \u2013 Butterfly valves Figure 9 \u2013 Segmented ball valve \u2013 90\u00b0travel <\/td>\n<\/tr>\n | ||||||
| 25<\/td>\n | Annex A (informative) Examples of given data <\/td>\n<\/tr>\n | ||||||
| 26<\/td>\n | Table A.1 \u2013 Calculation: Examples 1 to 3 <\/td>\n<\/tr>\n | ||||||
| 34<\/td>\n | Figure A.1 \u2013 The influence of the xFz value on prediction accuracy <\/td>\n<\/tr>\n | ||||||
| 35<\/td>\n | Bibliography <\/td>\n<\/tr>\n<\/table>\n","protected":false},"excerpt":{"rendered":" Industrial-process control valves – Noise considerations. Prediction of noise generated by hydrodynamic flow<\/b><\/p>\n |