1、BS ISO 9644:2008 ICS 65.060.35 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW BRITISH STANDARD Agricultural irrigation equipment Pressure losses in irrigation valves Test methodThis British Standard was published under the authority of the Standards Policy and Strategy Commit
2、tee on 31 July 2008 BSI 2008 ISBN 978 0 580 57363 7 Amendments/corrigenda issued since publication Date Comments BS ISO 9644:2008 National foreword This British Standard is the UK implementation of ISO 9644:2008. The UK participation in its preparation was entrusted to Technical Committee AGE/30, Ir
3、rigation and drainage equipment. A list of organizations represented on this committee can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British St
4、andard cannot confer immunity from legal obligations.BS ISO 9644:2008Reference number ISO 9644:2008(E) ISO 2008INTERNATIONAL STANDARD ISO 9644 Second edition 2008-07-01 Agricultural irrigation equipment Pressure losses in irrigation valves Test method Matriel agricole dirrigation Pertes de pression
5、dans les vannes dirrigation Mthode dessai BS ISO 9644:2008 ISO 9644:2008(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobes licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are licensed to and
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10、2008 All rights reservedBS ISO 9644:2008 ISO 9644:2008(E) ISO 2008 All rights reserved iii Contents Page Foreword iv 1 Scope . 1 2 Terms and definitions. 1 3 Test installation. 3 3.1 Permissible deviation of measuring devices. 3 3.2 Test equipment . 3 4 Test procedure 6 4.1 Test installation. 6 4.2
11、Test conditions . 6 4.3 Test bench pressure loss 7 4.4 Test of valve 8 5 Test results 8 5.1 Presentation of test results . 8 5.2 Calculated valve coefficients. 8 5.3 Test report . 10 Bibliography . 11 BS ISO 9644:2008 ISO 9644:2008(E) iv ISO 2008 All rights reservedForeword ISO (the International Or
12、ganization 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 which a technical committee has been establ
13、ished 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 matters of electrotechnical standardizati
14、on. 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 circulated to the member bodies for voting.
15、 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 responsible for identifying any or all such pa
16、tent rights. ISO 9644 was prepared by Technical Committee ISO/TC 23, Tractors and machinery for agriculture and forestry, Subcommittee SC 18, Irrigation and drainage equipment and systems. This second edition cancels and replaces the first edition (ISO 9644:1993), which has been technically revised.
17、 It also incorporates the Amendment ISO 9644:1993/Amd 1:1998. BS ISO 9644:2008 INTERNATIONAL STANDARD ISO 9644:2008(E) ISO 2008 All rights reserved 1 Agricultural irrigation equipment Pressure losses in irrigation valves Test method 1 Scope This International Standard specifies a test method for det
18、ermining the pressure loss in agricultural irrigation valves under steady-state conditions when water flows through them. The scope and accuracy of the valve performance specifications presented will assist agricultural irrigation system designers in comparing pressure losses through various types o
19、f valves. The measurement of pressure losses provides a means for determining the relationship between pressure loss and flow rate through the valve. This International Standard also describes the method of reporting pertinent test data. No attempt is made to define product use, design or applicatio
20、ns. The test method is suitable for valves with equal inlet and outlet nominal sizes. NOTE Unless otherwise specified, the equations are expressed in the SI units recommended by ISO 1000. 2 Terms and definitions For the purposes of this document, the following terms and definitions apply. 2.1 nomina
21、l size DN conventional numerical designation used to indicate the size of an irrigation valve NOTE It is expressed in millimetres, or in metres according to ISO 1000. 2.2 volume flow rate flow rate q Vvolume of water flowing through the valve per unit time NOTE It is expressed in litres per second (
22、l/s), cubic metres per hour (m 3 /h), or in cubic metres per second (m 3 /s) according to ISO 1000. BS ISO 9644:2008 ISO 9644:2008(E) 2 ISO 2008 All rights reserved2.3 pressure loss p difference in pressure due to water flow between two specified points in a system or in part of a system NOTE It is
23、expressed in pascals (Pa) according to ISO 1000, in kilopascals (kPa) or in bar 1) . 2.4 piping pressure loss p ppressure loss in the upstream and downstream portions of the test bench piping between the pressure taps, but excluding the pressure loss in the valve tested 2.5 bench pressure loss p bpr
24、essure loss in the test bench between the pressure taps upstream and downstream of the valve tested 2.6 valve pressure loss p vpressure loss in the valve tested 2.7 reference velocity refvelocity of flow through the valve calculated from the actual flow rate through the valve divided by the referenc
25、e cross-sectional area of the valve NOTE It is expressed in metres per second (m/s), in accordance with ISO 1000. 2.8 steady-state flow state of flow where the flow rate through a cross-section does not vary with time 2.9 valve flow coefficient K vnumber equal to the flow rate of water, in cubic met
26、res per hour, that will flow through a fully open valve with a one bar pressure loss across the valve NOTE It is expressed as 3 1 mh bar2.10 flow resistance coefficient coefficient used in non-dimensional presentation of valve loss 1) 1 bar = 0,1 MPa = 10 5 Pa; 1 MPa = 1 N/mm 2 . BS ISO 9644:2008 IS
27、O 9644:2008(E) ISO 2008 All rights reserved 3 3 Test installation 3.1 Permissible deviation of measuring devices The permissible deviation of the reading indicated on the measuring devices from the actual value shall be as follows: Flow rate: 2 % Differential and actual pressure: 2 % Temperature: 1
28、C The measuring devices shall be calibrated according to the existing calibration rules in the country concerned. 3.2 Test equipment 3.2.1 Piping Upstream and downstream piping shall be the same diameter as that of the test valve connection. The lengths of the straight, uniform-bore pipe shall be as
29、 specified in Figures 1 and 2. The inside surface of the piping shall be free of flaking rust, mill scale and irregularities which might cause excessive turbulence. In that part of the test apparatus shown within the frame, in Figures 1 and 2, the order of the fittings/devices shown in the key and t
30、he distances between them shall be adhered to, with the exception that the lengths indicated as 5d and 10d shall be understood to be the minimum allowable length. 3.2.2 Throttling valve A downstream throttling valve shall be used to control the flow through the test specimen. There are no restrictio
31、ns on the size or type of this valve. The throttling valve shall be located downstream of the downstream pressure tap (used for measuring bench pressure). 3.2.3 Flow measuring device Any device that can be used to measure flow with acceptable accuracy may be used. If a closed measuring device (such
32、as a rotameter, Venturi meter or similar device) is used, it shall be located either upstream of the upstream pressure tap or downstream of the downstream pressure tap. If an open measuring device (such as a calibrated volumetric tank) is used, it shall be located at the downstream end of the assemb
33、ly, i.e. downstream of the downstream throttling valve. The flow-measuring device shall be installed in accordance with the specific installation instructions and, where applicable, shall be installed with the required length of straight piping before and after the device. 3.2.4 Pressure differentia
34、l measuring device Any device capable of measuring pressure differential with acceptable accuracy may be used. BS ISO 9644:2008 ISO 9644:2008(E) 4 ISO 2008 All rights reserved3.2.5 Pressure taps Pressure taps (see Figure 3) shall be provided on piping for measurement of static pressure, and spaced a
35、s shown in Figures 1 or 2. The drilling centreline of the taps shall intersect the centreline of the pipe perpendicularly, as shown in Figure 3. The taps shall have a diameter, d 1 , of no less than 2 mm and no greater than 9 mm. The length, l, of the tap bore shall be not less than twice the diamet
36、er of the bore. For thin-walled pipes where the wall thickness is less than 2d 1 , a boss may be added to the pipe wall where the pressure taps are to be located (see Figure 3). Pressure taps shall be free of burrs and other irregularities and the inside wall of the piping shall be machine- finished
37、. For pipes of 50 mm diameter and larger, four taps shall be made, situated 90 5 apart on the circumference so that no tap is located on the lowest point of the pipe circumference. For pipe diameters of less than 50 mm, two taps will suffice. All taps, whether two or four in number, shall be connect
38、ed by a conduit whose bore shall not be less than two pressure-tap cross-sections. The pressure taps shall provide appropriate values of d 1and l, and may be made as illustrated in Figure 3. Key 1 controllable water supply 2 shut-off valve 3 pressure differential measuring device 4 test specimen, in
39、-line valve 5 temperature sensor 6 flow measuring device, closed type (if used) 7 throttling valve 8a pressure tap 8b pressure tap 9 pressure gauge 10 calibrated water tank (if used) d Nominal pipe diameter. NOTE Dimensions 5d and 10d are minimal values. Figure 1 Test circuit diagram for in-line val
40、ves BS ISO 9644:2008 ISO 9644:2008(E) ISO 2008 All rights reserved 5Key 1 controllable water supply 2 shut-off valve 3 pressure differential measuring device 4 test specimen, angle valve 5 temperature sensor 6 flow measuring device, closed type (if used) 7 throttling valve 8a pressure tap 8b pressur
41、e tap 9 pressure gauge 10 calibrated water tank (if used) d Nominal pipe diameter. NOTE Dimensions 5d and 10d are minimal values. Figure 2 Test circuit diagram for angle valves a) Thick wall b) Thin wall Figure 3 Static pressure taps in thick and thin-wall piping BS ISO 9644:2008 ISO 9644:2008(E) 6
42、ISO 2008 All rights reserved3.2.6 Temperature sensors Any temperature-sensing device that is capable of measuring water temperature with acceptable accuracy (see 3.1) may be used. The device shall be located upstream of the throttling valve. 3.2.7 Filtration If the valve manufacturer recommends the
43、use of filtered water, a manufacturer-recommended filter shall be installed upstream of the test circuit. 4 Test procedure 4.1 Test installation Install the test specimen on a suitable test bench for testing valves, as shown in Figure 1 or 2. Ensure that the water temperature during the test is betw
44、een 5 C and 35 C. 4.2 Test conditions 4.2.1 Permissible fluctuations in measurements For each quantity to be measured, the permissible amplitude of reading fluctuations is given in Tables 1 and 2. If fluctuations of greater amplitude are present, measurements may be carried out by providing a dampin
45、g device. The installation of the damping device shall not affect the accuracy of the readings. Symmetrical and linear damping devices shall be used. Table 1 Differential pressure fluctuation Flow resistance coefficient a p fluctuation % 20 6 4 u 20 10 1 u 4 17 0,1 u u 1 26 aSee 5.2.2. Table 2 Flowr
46、ate and pressure fluctuations Quantity Fluctuation % Flow rate, q V 3,5 Upstream pressure, e p 3,5 BS ISO 9644:2008 ISO 9644:2008(E) ISO 2008 All rights reserved 7 4.2.2 Steady conditions Test conditions are steady if the variations of each quantity, observed at the test operating point for at least
47、 10 s, do not exceed a value of 1,2 % (the difference between the largest and the smallest readings of the quantity related to the mean value). If this condition is met and if the fluctuations are less than the permissible values given in 4.2.1, only one set of readings of individual quantities is t
48、o be recorded for the test point considered. Record all readings only after steady flow conditions have been reached, and the flow is free from pulsations. 4.2.3 Unsteady conditions Test conditions are unsteady when variations exceed the limits of 4.2.2, when the following procedure shall be followe
49、d: At each test point, repeated readings of the measured quantities shall be made at random intervals of time, but not less than 10 s. A minimum of three sets of readings shall be taken at each test point, with more sets required as the fluctuation increases, as indicated in Table 3. Table 3 Minimum reading set requirements Number of sets Permissible difference between largest and smallest values of readings of each quantity, related to mean value % 3 1,8 5 3,5 7 4,5 9
