动力泵 - 水力性能验收试验 - 1级和2级

3.8 volume flow rate

outlet volume flow rate has the following value:

Q = q / ρ

NOTE In this International Standard the symbol Q may also designate the volume flow rate in any given section. It is the quotient of the mass flow rate in this section and the density. (The section may be designated by subscripts.)

3.9 mean velocity

mean axial velocity of flow equal to the volume flow rate divided by the pipe cross section area

u = Q / A

NOTE Attention is drawn to the fact that in this case Q may vary for different reasons across the circuit.

3.10 local velocity

velocity of flow at any point

3.11 head

energy per unit mass of fluid, divided by acceleration due to gravity, g

3.12 reference plane

any horizontal plane used as a datum for height measurement

NOTE For practical reasons it is preferable not to specify an imaginary reference plane.

3.13 height above reference plane

height of the considered point above the reference plane

NOTE Its value is:

• positive, if the considered point is above the reference plane;
• negative, if the considered point is below the reference plane.

See Figures 3 and 4.

6

Révision de la présente publication

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Terminologie

En ce qui concerne la terminologie générale, le lecteur se reportera à la Publication 50 de la CEI : Vocabulaire Electrotechnique International (VEI), qui est établie sous forme de chapitres séparés traitant chacun d'un sujet défini, l'Index général étant publié séparément. Des détails complets sur le VEI peuvent être obtenus sur demande.

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• la Publication 27 de la CEI : Symboles littéraux à utiliser en électrotechnique ;
• la Publication 617 de la CEI : Symboles graphiques pour schémas.

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Terminology

For general terminology, readers are referred to IEC Publication 50 : International Electrotechnical Vocabulary (IEV), which is issued in the form of separate chapters each dealing with a specific field, the General Index being published as a separate booklet. Full details of the IEV will be supplied on request.

The terms and definitions contained in the present publication have either been taken from the IEV or have been specifically approved for the purpose of this publication.

Graphical and letter symbols

For graphical symbols, and letter symbols and signs approved by the IEC for general use, readers are referred to :

• IEC Publication 27 : Letter symbols to be used in electrical technology ;
• IEC Publication 617 : Graphical symbols for diagrams.

The symbols and signs contained in the present publication have either been taken from IEC Publications 27 or 617, or have been specifically approved for the purpose of this publication.

IEC publications prepared by the same Technical Committee

The attention of readers is drawn to the inside of the back cover, which lists IEC publications issued by the Technical Committee which has prepared the present publication.

2

NORME INTERNATIONALE INTERNATIONAL STANDARD МЕЖДУНАРОДНЫЙ СТАНДАРТ

NORME INTERNATIONALE INTERNATIONAL STANDARD МЕЖДУНАРОДНЫЙ СТАНДАРТ

CEI IEC 50(426) Première édition First edition 1990-10 Vocabulaire Electrotechnique International Chapitre 426 : Matériel électrique pour atmosphères explosives International Electrotechnical Vocabulary Chapter 426 : Electrical apparatus for explosive atmospheres Международный Электротехнический Словарь Глава 426 : Электрооборудование для взрывоопасных сред © CEI 1990 Droits de reproduction réservés - Copyright - all rights reserved - Право издания охраняется законом Aucune partie de cette publication ne peut être reproduite ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie et les microfilms, sans l'accord écrit de l'éditeur. 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 the publisher. Запрещается Без письменного разрешения издателя воспроизведение или копирование этой публикации или ее части в любой форме или любыми средствами — электронными или механическими, включая фотоконю и микрофильм. Bureau central de la Commission Electrotechnique Internationale 3, rue de Varembé Genève Suisse Commission Electrotechnique Internationale International Electrotechnical Commission Международная Электротехническая Комиссия Code prix Price code Код цены S Pour prix, voir catalogue en vigueur For price, see current catalogue Цена указана в действующем каталоге 3

50(715) © IEC:1996

CONTENTS

FOREWORD	VII
PREFACE	VII
Sections
715-01	Basic terms	1
715-02	Resources	10
715-03	Calls	17
715-04	Times and delays	22
715-05	Traffic	24
715-06	Circuit groups	32
715-07	Traffic engineering	34
715-08	Networks	41
715-09	Circuit switched networks	46
715-10	Message switched networks	51
715-11	Packet switched networks	52
Index	53

:current

Foreword

This document (EN 10216-3:2002) has been prepared by Technical Committee EC/TC 29, "Steel tubes and fittings for steel tubes", the secretariat of which is held by UNI.

This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by November 2002, and conflicting national standards shall be withdrawn at the latest by November 2002.

This document has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association, and supports essential requirements of EU Directive(s).

For relationship with EU Directive(s), see informative annex ZA, which is an integral part of this document.

Other Parts of EN 10216 are:

Part 1:	Non-alloy steel tubes with specified room temperature properties
Part 2:	Non-alloy and alloy steel tubes with specified elevated temperature properties
Part 4:	Non-alloy and alloy steel tubes with specified low temperature properties
Part 5:	Stainless steel tubes

Another European Standard series covering tubes for pressure purposes is:

EN 10217:

Welded steel tubes for pressure purposes

According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom.

5

ISO 657-1 : 1988 (E)

Table 1 — Dimensions and sectional properties of hot-rolled equal-leg angles (concluded)

Designation	Mass kg/m	Sectional area cm²	Dimensions		Distances of centre of gravity		Sectional properties about axes
			X-X = Y-Y		U-U								V-V
			A mm	l mm	rroot mm	cx = cy cm	cu cm	cv cm	Ix = Iy cm⁴	rx = ry cm	Zx = Zy cm³	Iu cm⁴	ru cm	Iv cm⁴	rv cm	Zv cm³
(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)	(11)	(12)	(13)	(14)	(15)	(16)	(17)
200 × 200 × 16	48,5	61,8	200	16	18	5,52	14,1	7,81	2 340	6,16	162	3 720	7,76	960	3,94	123
200 × 200 × 20	59,9	76,3	200	20	18	5,68	14,1	8,04	2 850	6,11	199	4 530	7,70	1 170	3,92	146
200 × 200 × 24	71,1	90,6	200	24	18	5,84	14,1	8,26	3 330	6,06	235	5 280	7,64	1 380	3,90	167
250 × 250 × 28	104	133	250	28	18	7,24	17,7	10,2	7 700	7,62	433	12 200	9,61	3 170	4,89	309
250 × 250 × 35	128	163	250	35	18	7,50	17,7	10,6	9 260	7,54	529	14 700	9,48	3 860	4,87	364

NOTES

1. Member countries may choose, to be included in their national standards, the sizes which are required to meet their demand.
2. For the angles so chosen, only thicknesses which can be rolled in their mills to meet the demand of the users may be selected from the list of thicknesses corresponding to equal angles in table 1.
3. The sectional area has been calculated using the formula

   S = [l/2 A - l) + 0,214 6 (r_root² - 2r_toe²)] × 1/100

   where
   

   S is the sectional area, in square centimetres;
   

   l is the thickness, in millimetres;
   

   r_root is the root radius, in millimetres;
   

   r_toe is the toe radius, in millimetres;
   

   A is the leg length, in millimetres.

4. Mass is calculated on the basis of density of steel of 7,85 kg/dm³.

   4