1、INTERNATIONAL STANDARD IS0 9908 First edition 1993-l I-01 Technical specifications for centrifugal pumps - Class Ill Spdcifica tions techniques pour pompes ten trifuges - Classe 111 Reference number IS0 9908:1993(E) IS0 9908:1993(E) Contents Page Scope . . . . . . . . . . . . . . . . . . . . . . . .
2、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Normative references . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3、. 1 Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Shop inspection and tests , 7 Preparation for dispatch . . . .
5、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Annexes A B C D E F G Centrifugal pump - Data sheet . 9 Enquiry, proposal, purchase order . 14 Documentation . 15 Examples of seal arrangements 16 Piping arrangements for seals . 18 Chec
6、k list 21 Bibliography . 22 0 IS0 1993 All rights reserved. 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 per- mission in writing from the publisher. International Organization for Standa
7、rdization Case Postale 56 l CH-1211 Geneve 20 l Switzerland Printed in Switzerland ii IS0 9908:1993(E) Foreword IS0 (the International Organization for Standardization) is a worldwide federation of national standards bodies (IS0 member bodies). The work of preparing International Standards is normal
8、ly carried out through IS0 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
9、 work. IS0 collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requ
10、ires approval by at least 75 % of the member bodies casting a vote. International Standard IS0 9908 was prepared by Technical Committee ISO/TC 115, Pumps, Sub-Committee SC 1, Dimensions and technical specifications of pumps. Annexes A, B and C form an integral part of this International Standard. An
11、nexes D, E, F and G are for information only. IS0 9908:1993(E) Introduction This International Standard is the third of a set dealing with technical specifications of centrifugal pumps; they are designated as Classes I, II and III. Class I (see IS0 9905) comprises the most severe and Class III (this
12、 International Standard) the least severe requirements. For require- ments for Class II centrifugal pumps, see IS0 5199. The selection of the class to be used is made in accordance with the technical requirements for the application for which the pump is intended. The class chosen is to be agreed be
13、tween purchaser and manufacturer/supplier. The safety requirements of the field of application are furthermore to be taken into account. However, it is not possible to standardize the class of technical require- ments for centrifugal pumps for a certain field of application, because each field of ap
14、plication comprises different requirements. All classes (I, II and Ill) can be used in accordance with the different requirements of the pump application. It may happen that pumps built in accordance with Classes I, II and III may work beside each other in one plant. Further text covering specific a
15、pplications or industry requirements are dealt with later in separate standards. Criteria for the selection of a pump of the required class for a certain ap- plication may be based on: - reliability, - operating conditions, - environmental conditions. Throughout this International Standard, text wri
16、tten in bold letters indi- cates where a decision may be required by the purchaser, or where agreement is required between the purchaser and manufacturer/supplier. INTERNATIONAL STANDARD IS0 9908:1993(E) Technical specifications for centrifugal pumps - Class Ill 1 Scope 1.1 This International Standa
17、rd covers Class III re- quirements for centrifugal pumps of single stage, multistage, horizontal or vertical construction (coupled or close-coupled) with any drive and any installation for general application. 1.2 This International Standard includes design fea- tures concerned with installation, ma
18、intenance and safety of such pumps including baseplate, coupling and auxiliary piping but excluding the driver, if it is not an integral part of the pump. 1.3 Where the application of this International Stan- dard has been called for: a) and requires a specific design feature, alternative designs ma
19、y be offered which meet the intent of this International Standard provided that the alternative is described in detail. b) pumps not complying with all requirements of this International Standard may be offered for con- sideration, provided that all deviations are stated. 2 Normative references The
20、following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publi- cation, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard a
21、re encouraged to investigate the possibility of applying the most re- cent editions of the standards indicated below. 1) To be published. Members of IEC and IS0 maintain registers of cur- rently valid International Standards. IS0 76:1987, Rolling bearings - Static load ratings. IS0 281 :1990, Rollin
22、g bearings - Dynamic load ratings and rating life. IS0 2372: 1974, Mechanical vibration of machines with operating speeds from 10 to 200 rev/. - Basis for specifying evaluation standards. IS0 2548:1973, Centrifugal, mixed flow and axial pumps - Code for acceptance tests - Class C f/t is planned to c
23、ombine IS0 2548 with IS0 3555 during their next revision ro create a new lntemational Stan- dard). IS0 3069: 1974, End suction centrifugal pumps - Di- mensions of cavities for mechanical seals and for soft packing. IS0 3555:1977, Centrifugal, mixed flow and axial pumps - Code for acceptance tests -
24、Class B (It is planned to combine IS0 3555 with IS0 2548 during their next revision to create a new International Stan- dard). IS0 7005-I :1992, Metallic flanges - Part 1: Steel flanges. IS0 7005-2:1988, Metallic flanges - Part 2: Cast iron flanges. IS0 7005-3:1988, Metallic flanges - Part 3: Copper
25、 alloy and composite flanges. IS0 9905:-I, Technical specifications for centrifugal pumps - Class I. 3 Definitions b) data sheet (see annex A); For the purposes of this International Standard, the definitions given in IS0 9905 and the following defi- nitions apply. 3.1 rated conditions: Conditions (
26、driver excluded) that define the (guarantee) point necessary to meet all defined operating conditions, taking into account any necessary margins. NOTE 1 This definition differs slightly from that given in IS0 9905. 3.2 rated driver output: The maximum permissible driver power output under site opera
27、ting conditions. 3.3 pressure-temperature rating: Relationship be- tween pressure and temperature given in the form of a graph (see figure 1). 4 Design 4.1 General Whenever the documents include contradicting tech- nical requirements, they apply in the following se- quence: a) purchase order (or enq
28、uiry if no order is placed) (see annex B); Basic design pressure Operating pressure c) this International Standard; d) other standards to which reference is made in the order (or enquiry if no order is placed). 4.1.1 Characteristic curve The characteristic curve shall indicate the allowable operatin
29、g range of the pump. 4.1.2 Net positive suction head (NPSH) The NPSHR shall be based on cold water as specified in IS0 2548 and IS0 3555. The NPSHA must exceed NPSHR by a margin of at least 0,5 m. The basis for use in performance curves is that NPSH correspond- ing to a drop of 3 % of the total head
30、 of the first stage of the pump (NPSH3). 4.1.3 Installation The pumps should preferably be suitable for outdoor installation under normal environmental conditions. If they are suitable only for indoor installation this infor- mation shall be clearly stated in the manufacturer/ suppliers documentatio
31、n. For outdoor installation, the range of environmental conditions shall be specified by the purchaser. Operatlng pressure Temperature Figure 1 - Relationship between temperature and pressure IS0 9908:1993(E) 4.2 Prime movers 4.2.1 Defined operating conditions Prime movers required as driver for cou
32、pled pumps shall have power output ratings at least equal to the percentage of rated pump power input given in figure2 for the range of 1 kW to 100 kW. For pump power input outside this range, the percentage is to be agreed upon between manufacturer/sup- plier and purchaser. Where the prime mover ha
33、s an output rating covering the power requirements at any operating conditions of the impeller diameter in- stalled, no extra margins are required. 4.2.2 Undefined operating conditions Prime movers as drivers for close-coupled pumps shall have power output ratings covering the power requirements at
34、any operating conditions of the impeller diameter installed. These conditions elimin- ate the need for extra margins. 0.5 i 5 lb 50 100 kW Pump power input at rated conditions Figure 2 - Driver output percentage of rated pump power required in the range 1 kW to 100 kW 3 IS0 9908:1993(E) 4.3 Critical
35、 speed, balance and vibration gle operating point at rated speed (* 5 %) and rated flow (+ 5 %) when operating without cavitation. 4.3.1 Critical speed Under operating conditions, the actual first lateral critical speed of the rotor when coupled to the drive agreed upon shall be at least 10 % above
36、the maxi- mum allowable continuous speed including the trip speed of a turbine-driven pump. For vertical lineshaft pumps, a flexible shaft is permitted. 4.3.2 Balance and vibration 4.3.2.1 Horizontal pumps Pumps with a special impeller, for example a single channel impeller, may exceed the limits gi
37、ven in table 1. In such case the pump manufacturer/supplier should indicate this in his offer. 4.3.2.2 Vertical lineshaft pumps a) Vibration readings shall be taken on the top flange of the driver mount on vertical lineshaft pumps with rigid couplings and near to the top pump bearing on vertical pum
38、ps with flexible couplings. Unfiltered vibration shall not exceed the vibration se- b) Vibration limits for both rolling and sleeve bearing verity limits given in table 1 when measured on the pumps shall not exceed a velocity of 7,l mm/s manufacturer/suppliers test facilities. These values rms durin
39、g shop test at rated speed (+ 5 %), and are measured radially at the bearing housing at a sin- rated flow (& 5 %) operating without cavitation. Table 1 - Limits of vibration severitv for horizontal DumDs with multivane imoellers Speed of rotation n min-1 n 225 mm 23 43 1 800n 4 500 4,5 7,l 1) Based
40、on IS0 2372. 2) For horizontal foot-mounted pumps, h, is the distance between baseplate area in contact with pump feet and pump shaft centreline. 4.4 Pressure-containing parts 4.4.1 Pressure-temperature rating The pressure limit (maximum allowable working pressure) of the pump at the most severe ope
41、rating conditions shall be clearly defined by the manufacturer/supplier. In no case may the rated pressure of the pump (casing and cover, including shaft seal housing and gland follower/end plate) ex- ceed that of the pump flanges. The basic design pressure of the pump shall be a gauge pressure of a
42、t least 6 bar2) at 20 “C when made of cast iron, ductile iron, carbon steel or stainless steel. For materials the tensile requirements of which do not permit the 6 bar rating, the pressure-temperature rat- ing shall be adjusted according to the stress- temperature rating for the material and shall b
43、e clearly stated by the manufacturer/supplier. Low head pumps may have a lower pressure- temperature rating if this is clearly stated by the manufacturer/supplier on the nameplate and data sheet. 4.4.2 Wall thickness Pressure casings including the shaft seal housing and gland end plate shall be of s
44、uch thickness as will be suitable for containing pressure and limiting distortion under the maximum allowable working pressure at operating temperature. The casing shall also be suitable for the hydrostatic test pressure (see clause 6) at ambient temperature. 4.4.3 Materials The materials used for p
45、ressure-containing parts shall depend on the liquid pumped and the application of the pump (see clause 5). 4.4.4 Mechanical features 4.4.4.1 Dismantling The pump should be designed to permit necessary dismantling for spare part replacement without dis- turbing inlet and outlet connections. If the de
46、sign is such that dismantling will cause some disturbance, then it should be so stated. 4.4.4.2 Casing gaskets Casing gaskets shall be of a design suitable for the rated operating conditions and for hydrostatic test conditions at ambient temperature. 2) 1 bar = 0,l MPa 4.4.4.3 External bolting Bolts
47、 or studs that connect pressure-containing parts shall be selected to be adequate for the maximum allowable working pressure and for normal tightening procedures. 4.5 Branches (nozzles) and miscellaneous connections NOTE 2 For the purpose of this International Standard the terms branch and nozzle ar
48、e synonymous. 4.5.1 Type and size Type and size of fluid connections shall be stated in the manufacturer/suppliers document. 4.5.2 Closures Vent, pressure-gauge and drain openings shall be fit- ted with removable closures adequate to contain the maximum allowable working pressures and of ma- terial
49、suitable for the pumped liquid. 4.6 External forces and moments on branches (inlet and outlet) The manufacturer/supplier shall provide details of al- lowable external forces and moments on branches on request. 4.7 Branch (nozzle) flanges If circular flanges are used the flange envelope shall be of a size to enable flanges as specified in IS0 7005-1, IS0 7005-2 and IS0 7005-3 to be used. If the pump manufacturer/suppliers standard pat- tern entails a flange thickness and a diameter greater than that of the rating specified, the heavier flange may be supplied if requested by the manufactur
