1、 g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58applicationsICS 23.080Pumps Testing Submersible mixers for wastewater and similar BRITISH STANDARDB
2、S ISO 21630:2007BS ISO 21630:2007This British Standard was published under the authority of the Standards Policy and Strategy Committee on 28 September 2007 BSI 2007ISBN 978 0 580 56041 5Amendments issued since publicationAmd. No. Date CommentsCompliance with a British Standard cannot confer immunit
3、y from legal obligations. National forewordThis British Standard is the UK implementation of ISO 21630:2007.The UK participation in its preparation was entrusted to Technical Committee MCE/6, Pumps and pump testing.A list of organizations represented on this committee can be obtained on request to i
4、ts secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Reference numberISO 21630:2007(E)INTERNATIONAL STANDARD ISO21630First edition2007-08-15Pumps Testing Submersible mixers for wastewater and similar a
5、pplications Pompes Essais Mlangeurs immergs pour eaux uses et applications similaires BS ISO 21630:2007ii iiiContents Page Foreword iv Introduction v 1 Scope . 1 2 Terms and definitions. 1 3 Symbols and abbreviated terms . 3 4 Guarantees 4 4.1 Subjects of guarantees 4 4.2 Conditions of guarantees 5
6、5 Execution of tests. 5 5.1 Subjects of tests . 5 5.2 Organization of tests 6 5.3 Test arrangements 8 5.4 Test conditions . 8 6 Analysis of test results. 11 6.1 Translation of the test results to the guarantee conditions. 11 6.2 Measurement uncertainties . 12 6.3 Values of tolerance factors 13 6.4 V
7、erification of guarantees 14 7 Measurement of thrust . 15 7.1 Flow conditions of mixer thrust measurement 15 7.2 Mixer thrust measurement method. 18 7.3 Uncertainty of measurement . 18 8 Measurement of mixer electric power uptake 19 Annex A (informative) Checklist . 20 Bibliography . 21 BS ISO 21630
8、:2007iv Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for w
9、hich 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 work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all
10、 matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are c
11、irculated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held resp
12、onsible for identifying any or all such patent rights. ISO 21630 was prepared by Technical Committee ISO/TC 115, Pumps, Subcommittee SC 2, Methods of measurement and testing. BS ISO 21630:2007vIntroduction This International Standard prescribes acceptance test methods for submersible mixers for wast
13、ewater and other applications. It is intended for performance measurements relevant to submersible mixers bearing in mind the similarities to, and crucial differences from, submersible pumps. Hence head (pressure) and flow rate measurements are not included. The basic output performance parameter is
14、 the thrust. As continuous operation is commonplace, electric power consumption is important for the Life Cycle Cost, and is put forward as an important parameter. It is acknowledged that the present International Standard draws heavily on ISO 9906:1999 in the generalities. The major objectives of t
15、his International Standard are to increase uniformity/compatibility in equipment performance characterization, enabling a comparison of mixers, simplify communication between customer and supplier and protect customers, reduce the need for documentation, increase quality and efficiency in both machi
16、nery and process. BS ISO 21630:2007blank1Pumps Testing Submersible mixers for wastewater and similar applications 1 Scope This International Standard prescribes acceptance test methods for submersible mixers (hereafter “SM” or “mixer”) used for mixing in wastewater and other applications where at le
17、ast one system component is a liquid. “Submersible mixer” is taken to mean a fully submersible aggregate consisting of a drive unit and an axial flow type impeller, and optional parts, such as shrouds, supporting the basic functions. “Liquid” is taken to mean a body without capacity to accommodate s
18、hear stresses when at rest. This includes suspensions and dispersions (liquid/solid, gas/liquid and gas/liquid/solid), and non-Newtonian liquids, provided that a possible small yield stress does not prevent the liquid from flowing when agitated. 2 Terms and definitions For the purposes of this docum
19、ent, the following terms and definitions apply. 2.1 thrust-to-power ratio ratio of mixer thrust force to mixer power consumption RFP= F / P1NOTE 1 The ratio of minimum required mixing system power dissipation to mixer power consumption is an (end-user oriented) system efficiency. To understand the i
20、mportance of the thrust-to-power ratio, consider the case of an SM generating a longitudinal flow velocity u in a recirculation channel such as a wastewater oxidation ditch. This is in fact a common application of the SM, and the following argument is in principle possible to generalize to other app
21、lications. The momentum loss of the flow over one circulation equals the rate of momentum provided by the SM at quasi-steady state. This is given by the mixer thrust F. The power dissipated as a result of this momentum loss is P = F u, and this is the minimum required mixing system power to maintain
22、 the velocity u. Hence, the system efficiency is P / P1= F u / P1. It is possible to isolate the mixer properties from the system requirement in this expression, and this leads to the thrust-to-power ratio, RFP, as the most relevant efficiency-related parameter of the SM. It should be noted that it
23、is dimensional, and hence it depends on the impeller diameter and speed, not only on the impeller geometry. Other considerations than energetic efficiency of generation of longitudinal flow provide for the multitude of impeller diameters and speeds available in practice. NOTE 2 An impeller efficienc
24、y, defined as the ratio of power of axial motion of the impeller discharge to the electric power uptake of the mixer, can be defined. The definition draws on the assumption that the approaching velocity, u, is small enough to have negligible influence on the mixer impeller characteristics. The hydra
25、ulic discharge power Ph= p Q can be expressed in thrust using the relations p = F / A and F = 2 Q2/ A which are approximately valid for the mixer test established herein. The conventional area of the vena contracta A / 2 is used, as this discharge section best fulfils the flat velocity profile requi
26、rement. With A = D2/ 4, one obtains Ph= (F / A) (A F / 2 )1/2= F3/2/ D ( / 2)1/2 BS ISO 21630:20072 Hence the impeller efficiency can be written = F3/2/ ( / 2)1/2D P1 It can be noted that, often correct to within 1 %, the efficiency is conventionally given as (assuming SI units F = Newton, P1 = Watt
27、, D = meter, and clean cold water as defined in 5.4.5.2) = F3/2/ (40 D P1) Although the derivation given here is not based on completely correct assumptions, the approximate expression for the efficiency may be derived in more rigorous ways. The value of the impeller efficiency alone is not deemed t
28、o be of primary interest because of the dependency of mixer-system efficiency on the impeller diameter and speed. 2.2 advance ratio ratio of propeller traversing speed or mean liquid ambient speed to (essentially) tip speed J = u / nD 2.3 impeller Reynolds number ratio between inertial and viscous f
29、orces prevailing at impeller Re = (F / )1/2/ NOTE F is the thrust for the same mixer running at the same speed in clean cold water as defined in 5.4.5.2. Also note that this is not the same as the blade Reynolds number, nor is it identical, but akin to the impeller Reynolds number used for dry-insta
30、lled agitators in the process industries. BS ISO 21630:200733 Symbols and abbreviated terms Table 1 summarizes the symbols in alphabetical order and SI units used. Table 1 Alphabetical list of letters used as symbols Symbol Quantity Unit A Area swept by impeller m2D Diameter of impeller m e Uncertai
31、nty, relative (pure number), % f Frequency s1, Hz F Thrust NJ Propeller advance ratio (pure number) L Length of lever m n Speed of rotation s1, Hz p Pressure Pa P Power WQ Flow rate m3/s RFPThrust-to-power ratio N/W Re Impeller Reynolds number (pure number) t Tolerance (pure number), % T Time su Mea
32、n velocity in the axial or longitudinal direction m/s U Voltage V x Generic measured entity Time average of x Efficiency (pure number), % Kinematic viscosity m2/s Density kg/m3 Standard deviation BS ISO 21630:20074 Table 2 summarizes the subscripts used for the symbols. Table 2 Alphabetical list of
33、letters and figures other than above used as subscript Subscript Meaning 1 electric (power) G guaranteed L/L length ratio h hydraulic (power) LC load cell related m measured M mixer related FP see RFPsp specified Tr translated TS time series 4 Guarantees 4.1 Subjects of guarantees 4.1.1 General Term
34、s used herein such as “guarantee” or “acceptance” should be understood in a technical but not in a legal sense. The term “guarantee” therefore specifies values for checking purposes determined in the contract, but does not say anything about the rights or duties arising if these values are not reach
35、ed or fulfilled. The term “acceptance” does not have any legal meaning here, either. Therefore, an acceptance test carried out successfully alone does not represent an “acceptance” in the legal sense. A procedure for verifying the guarantees is given in 6.4. 4.1.2 Thrust guarantee One guarantee poin
36、t shall be defined by a guarantee thrust FG. The manufacturer/supplier guarantees that under the standard test conditions established in this document, the measured thrust will fall in a specified interval surrounding FG. Unless otherwise stated, the interval is given by the tolerances stated in Tab
37、le 6. 4.1.3 Electric power uptake guarantee One guarantee point shall be defined by a guarantee electric power uptake P1G. The manufacturer/supplier guarantees that under the standard test conditions established in this document, the measured electric power uptake will fall in a specified interval s
38、urrounding P1G. Unless otherwise stated, the interval is given by the tolerances stated in Table 6. BS ISO 21630:200754.1.4 Thrust-to-power ratio guarantee One guarantee point shall be defined by a guarantee thrust-to-power ratio RFP,G. This shall be given by RFP,G= FG/ P1G. The manufacturer/supplie
39、r guarantees that under the standard test conditions established in this document, the measured and calculated thrust-to-power ratio will fall in a specified interval surrounding RFP,G. Unless otherwise stated, the interval is given by the tolerances stated in Table 6. 4.2 Conditions of guarantees U
40、nless otherwise agreed, the following conditions shall apply to the guaranteed value. a) The guarantee point shall apply to clean cold water (see 5.4.5.2). b) The relationship between the guarantee values under clean cold water conditions and the likely performance under other liquid conditions shal
41、l be agreed in the contract. c) Guarantees shall apply only to the mixer as tested by the methods and in the test arrangements specified herein. d) The relationship between the guarantee values under the conditions of the methods and test arrangements specified herein and the likely performance unde
42、r other operating conditions shall be agreed in the contract. 5 Execution of tests 5.1 Subjects of tests 5.1.1 General If not otherwise agreed between the manufacturer/supplier and the purchaser, the following shall apply: accuracy according to 6.2; and tests shall be carried out on the test stand o
43、f the manufacturers works, or on a test stand engaged by the manufacturer/supplier. Any deviations from this shall be agreed between the purchaser and manufacturer/supplier. This should be done as soon as possible, and should preferably form part of the contract. Among others, such deviations may be
44、 a) accuracy other than that given in 6.2, b) tolerance factors other than those given in 6.3, c) tests in a neutral laboratory. Annex A shows a checklist of items where agreement between the purchaser and manufacturer/supplier is recommended. BS ISO 21630:20076 5.1.2 Contractual tests Fulfilment of
45、 the guarantee The tests are intended to ascertain the performance of the mixer and to compare this with the manufacturers/suppliers guarantee. The nominated guarantee for any quantity shall be deemed to have been met if, when tested according to this International Standard, the measured performance
46、 falls within the tolerance specified for the particular quantity. When a number of identical mixers are to be purchased, the number of mixers to be tested shall be agreed upon between the purchaser and the manufacturer/supplier. 5.2 Organization of tests 5.2.1 General Both purchaser and manufacture
47、r/supplier shall be entitled to witness these tests. The test supervisor may delegate his/her responsibilities under 5.2.4 to the test operator, provided the test operator is sufficiently trained to handle these responsibilities. 5.2.2 Location of tests Performance tests should preferably be carried
48、 out at the manufacturers works, or at another test stand engaged by the manufacturer/supplier, or at a place to be mutually agreed between the manufacturer/supplier and the purchaser. 5.2.3 Date of testing The date of testing shall be mutually agreed by the manufacturer/supplier and the purchaser i
49、f the purchaser by contract requires to witness the test. 5.2.4 Staff Accurate measurements depend not only on the quality of the measuring instrument used but also on the ability and skill of the persons operating and reading the measurement devices during the tests. The staff entrusted with effecting the measurements shall be selected just as carefully as the instruments to be used in the test. Specialists with adequate experience in measuring operations in general shall be
