1、June 2008DEUTSCHE NORM English price group 27No part of this standard may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 91.140.40!$O Vcis the vol
2、ume in cubic metres (m3)that has actually flowed through the meter 3.1.8 external leak tightness leak tightness of the gas carrying components of the gas meter with respect to the atmosphere 3.1.9 flag single alphabetic character on the index giving a visual signal of significant events and/or chang
3、e(s) in the operation of the meter 3.1.10 galvanic connection/interface hard wired serial connection or pulse output from the meter 3.1.11 index all that which is viewed through the index window, including the display 3.1.12 index window(s) area(s) of transparent material through which the index can
4、 be read 3.1.13 maximum error shift maximum mean error shift at any of the tested flow rates 3.1.14 maximum working pressure upper limit of the working pressure for which the meter has been designed, as declared by the manufacturer and marked on the index or the data plate 3.1.15 mean error arithmet
5、ic mean of consecutive errors of indication at a flow rate 3.1.16 measuring element part of the meter which produces an electrical signal proportional to the gas flow rate DIN EN 14236:2008-06 EN 14236:2007 (E) 12 3.1.17 memory element which stores digital information 3.1.18 meter case complete mete
6、r, not casing only 3.1.19 meter class class to which a meter belongs, according to the metrological requirements of this European Standard, i.e. class 1,5 or class 1,0. 3.1.20 meter cover rigid enclosure on the front of the meter made either wholly of transparent material, or of opaque material prov
7、ided with index window(s) 3.1.21 normal conditions of operation conditions referring to the meter operating: at a pressure up to the maximum working pressure (with or without a flow of gas); within the range of flow rates; within the ambient temperature range; within the gas temperature range; with
8、the distributed gas 3.1.22 operating mode method (sample frequency and timing) of obtaining volume flow measurements 3.1.23 optical port serial data port using an infra-red transmitter and receiver 3.1.24 pressure absorption difference between the pressure measured at the inlet and outlet connection
9、s of the meter whilst the meter is operating 3.1.25 pressure measuring point permanent fitting on the meter outlet enabling a direct measurement of the outlet pressure to be obtained 3.1.26 range of mean errors difference between the minimum and maximum mean errors over a specified flow range 3.1.27
10、 regression line straight line, generated using a statistical method, to give a graphical representation of a set of results DIN EN 14236:2008-06 EN 14236:2007 (E) 13 3.1.28 register electronic device comprising both memory and display, which stores and displays information 3.1.29 segment individual
11、 part of a display which is able to show a portion of a character 3.1.30 starting flow rate lowest flow rate at which the meter is able to indicate a volume of gas passed 3.1.31 temperature conversion device device which converts the measured volume to a corresponding volume at base gas temperature
12、3.1.32 test house organisation used to perform prescribed tests on meters, in accordance with this standard 3.1.33 thermal cut-off valve heat sensitive valve used to cut off the flow of gas to the meter if the ambient temperature rises above a predetermined level for a specified time 3.1.34 ultrason
13、ic gas meter gas meter that uses ultrasound and that is designed to measure, memorise and display the fuel gas volume that has passed through it 3.1.35 ultrasonic transducer device used to generate and detect the ultrasound signals within the meter 3.1.36 working pressure pressure of the gas at the
14、inlet of the meter 3.2 Symbols 3.2.1 D outside diameter of the pipe in millimetres (mm) 3.2.2 g acceleration due to gravity, in metres per square second (m s-2) 3.2.3 MPE maximum permissible error, in percent (%) 3.2.4 pmaxmaximum working pressure DIN EN 14236:2008-06 EN 14236:2007 (E) 14 3.2.5 Qmax
15、 maximum flow rate, specified in cubic metres per hour (m3/h) for which the meter has been designed 3.2.6 Qmin minimum flow rate, specified in cubic metres per hour (m3/h) for which the meter has been designed 3.2.7 Qr overload flow rate, the highest flow rate at which the meter operates for a short
16、 period of time without deteriorating 3.2.8 Qstart lowest flow rate at which the meter is capable of registering the passage of gas, as declared by the manufacturer 3.2.9 Qt transitional flow rate, occurring between the maximum and minimum flow rates at which the flow rate range is divided into two
17、zones, the upper zone and the lower zone NOTE Each zone has a characteristic maximum permissible error 3.2.10 tbbase gas temperature 3.2.11 tb,ibase gas temperature for meters declared suitable for differential temperature and intermittent operation 3.2.12 Ti temperature at meter inlet 3.2.13 tm amb
18、ient temperature of the meter 3.2.14 tg gas temperature range of the meter 3.2.15 tsp specified centre temperature for a temperature converted meter 4 Normal operating conditions 4.1 Flow range The values of maximum flow rates and those corresponding values of the upper limits of the minimum flow ra
19、tes shall be those given in Table 1. DIN EN 14236:2008-06 EN 14236:2007 (E) 15 Table 1 Flow range QmaxUpper limits of Qminm3/h m3/h 2,5 0,016 4 0,025 6 0,040 10 0,060 The definitions of the meter classifications applicable in this European Standard are given in Table 2. Table 2 Flow rate ranges by m
20、eter classification Class Qmax/QminQmax/QtQr/Qmax1,5 150 10 1,2 1,0 150 5 1,2 4.2 Maximum working pressure The manufacturer shall declare the maximum working pressure of the meter and this pressure shall be marked on the index or data plate of the meter. This pressure shall not exceed 0,5 bar. 4.3 T
21、emperature range Unless otherwise stated, all temperatures given in this document shall be measured to within 1 C. All meters shall be capable of meeting the requirements for a minimum ambient temperature range of -10 C to +40 C (see 5.14), a minimum gas temperature span of 40 K and a storage temper
22、ature of -20 C to +60 C. The gas temperature range shall be within the ambient temperature range. The manufacturer shall declare the gas temperature range and the ambient temperature range. The manufacturer can declare a wider ambient temperature range using a minimum temperature of -10 C, -25 C or
23、-40 C and a maximum temperature of 40 C, 55 C or 70 C and/or a wider storage temperature range. The meter shall be capable of meeting the requirements over this declared wider range. If the manufacturer declares that the meter is resistant to high ambient temperatures, the meter shall also be capabl
24、e of meeting the requirements of the heat resistance test and shall be marked accordingly (see 7.2.1 and 9.1). DIN EN 14236:2008-06 EN 14236:2007 (E) 16 4.4 Range of gases 4.4.1 Test gases The manufacturer shall specify the range of gases for which the meter is suitable, from Table 3. Table 3 Gas gr
25、oups from EN 437 Second family Groups H L E Third family Groups P/B P B Additional Air Meters suitable for: second family gases shall be tested with air and 99,5 % CH4. third family gases shall be tested with air and 99,5 % Propane and/or 99,5 % Butane, as appropriate. By agreement with the Test Hou
26、se any other test gas can be included. The additional gases shall be marked on the meter as defined in 9.1. NOTE For further information on test gases see Annex A. 4.5 Orientation Where meters can be installed in orientations other than with the connection ports vertical, meters shall be tested in t
27、hose other orientations, for durability and as agreed with the Test House. 5 Metrological performance 5.1 General Provision shall be made for synchronizing the start and finish of test periods with test equipment, either via a galvanic connection or optical port. The test equipment shall generate an
28、 event that starts the test. The measured response (volume reading) from the meter shall be synchronous with its sampling instant. To achieve this, the meter shall delay its measured response until the next sample period after it has received a start command. The sampling instant shall be synchronou
29、s with the start of the data transmission string. NOTE This is used to start/stop an independent timer of sufficient resolution to accurately time the period between successive measure periods. If it is intended to use the meter in two directions (forward and reverse flow) then all tests shall be pe
30、rformed in both directions. DIN EN 14236:2008-06 EN 14236:2007 (E) 17 5.2 Mode comparison 5.2.1 General If the meter has a normal operating (sampling) mode and one or more test (fast sampling) modes then, provided that the requirement in 5.2.2 is met, all subsequent tests in this European Standard s
31、hall be carried out in the test-mode. If the requirement is not satisfied then all subsequent tests shall be performed in the normal operating mode. 5.2.2 Requirements The accuracy of the measurements shall not be influenced by different sampling modes. The difference of the mean errors of the stand
32、ard mode and the test-mode shall not exceed 0,3 % for Qt Q Qmaxand 0,6 % for Qmin Q Qt. If this requirement is not satisfied, subsequent tests shall be undertaken in the normal operating mode. 5.2.3 Test Test the meter in the standard mode and in the test-mode in accordance with 5.3.2 a). Calculate
33、the difference in mean error at each flow rate. 5.3 Permissible errors 5.3.1 Requirements When tested in accordance with 5.3.2 a) the mean error shall be within the maximum permissible errors specified in Table 4 and the range of mean errors shall be within the limits specified in Table 5. When the
34、errors between Qtand Qmaxall have the same sign, they shall not exceed 1 % for class 1,5 and 0,5 % for class 1,0. When tested in accordance with 5.3.2 b) the mean error shall be within the maximum permissible errors specified in Table 4 and the range of mean errors shall be within the limits specifi
35、ed in Table 5 for each individual test gas at each test temperature. If the manufacturer has declared a wider ambient and gas temperature range, then the extreme temperatures declared shall be substituted for -10 C and +40 C, as appropriate. After the meter has been subjected to other influences, gi
36、ven by the individual clauses of this European Standard, the mean errors shall be within the error limits specified within those clauses when tested by the methods given in 5.3.2 a) or 5.3.2 b). 5.3.2 Test a) Error on air Thermally stabilize the meter to be tested to the temperature of the test labo
37、ratory. Pass a volume of air at 20 C, the actual volume of which is measured by a reference standard, through the meter and note the volume indicated by the meter. This indicated volume can be obtained via the communication port. The minimum volume of air to be passed through the meter is specified
38、by the manufacturer and agreed with the Test House. DIN EN 14236:2008-06 EN 14236:2007 (E) 18 Carry out six consecutive tests at each of the following flow rates in ascending or descending order Qmin, 3 Qmin, 5 Qmin, 10 Qmin, 0,1 Qmax, 0,2 Qmax, 0,4 Qmax, 0,7 Qmax, Qmax. Calculate the six errors of
39、indication (see 3.1.7) at each of the flow rates, the mean of the six errors and note it as a point on the error curve. Then, calculate the difference of the arithmetic mean of the errors of indication at each of the flow rates. b) Error on gas (excluding air) Carry out the test as described in 5.3.
40、2 a) and additionally at 10 C and +40 C (or that wider temperature range declared by the manufacturer) using the test gases in turn specified in 4.4.1 and any other test gas by agreement with the Test House, which shall be marked on the meter (see 9.1). Table 4 Maximum permissible errors, class 1,5
41、and class 1,0 Maximum permissible errors Flow rate m3/h Class 1,5 Class 1,0 Qmin Q Qt 3 % 2 % Qt Q Qmax 1,5 % 1 % Table 5 Maximum difference between errors Flow rate range Maximum range of mean errors m3/h Class 1,5 Class 1,0 Qmin Q Qt. 4 % 11/3% Qt Q Qmax2 % 2/3% 5.4 Gas air relationship 5.4.1 Gene
42、ral Where meters satisfy the requirements in 5.4.2, air shall be used for subsequent tests as the test medium. 5.4.2 Requirements When tested in accordance with 5.4.3 the range of mean errors on all test gases combined (including air) shall be within the limits specified in Table 5 (see X in Figure
43、1). The difference between the mean error on the test gases and that on air at each flow rate shall satisfy the limits specified in Table 6 (see Y in Figure 1). Table 6 Mean error difference between gas and air Flow rate Maximum mean error difference m3/h Class 1,5 Class 1,0 Qmin Q Qt 3 % 2 % Qt Q Q
44、max 1,5 % 1 % NOTE Figure 1 represents a graphical explanation of the requirements given in 5.3 and 5.4. DIN EN 14236:2008-06 EN 14236:2007 (E) 19 Q minQ maxQt1231.5XY-1.5-3Key 1 error % 2 flow rate Q error on gas error on air NOTE All points are the mean of at least 3 measurements. Figure 1 Relatio
45、nship between defined errors 5.4.3 Test Apply the requirements of 5.4.2 to the results from testing the meter in accordance with 5.3.2 a) and 5.3.2 b). 5.5 Pressure absorption 5.5.1 Requirements The pressure absorption of the meter with a flow of air of density 1,2 kg/m3, at a flow rate equal to Qma
46、x, shall not exceed 2,0 mbar. 5.5.2 Test Pass air through the meter with a flow of air of density 1,2 kg/m3, at a flow rate equal to Qmax, and measure the differential pressure across the meter with a suitable measuring instrument. DIN EN 14236:2008-06 EN 14236:2007 (E) 20 5.6 Metrological stability
47、 5.6.1 Requirements The difference between any two of the six errors of indication at each flow rate greater than or equal to Qtshall not exceed 0,6 % and at each flow rate less than Qtthe difference shall not exceed 1,0 %. 5.6.2 Test Apply the requirements of 5.6.1 to the results from testing the m
48、eter in accordance with 5.3.2 a). 5.7 Immunity to contaminants in gas stream 5.7.1 Requirements When meters are tested in accordance with 5.7.2, the errors of these meters shall not exceed the following: Class 1,5 Mean error: 2 MPE; Error shift: 2 % between Qtto Qmax. Class 1,0 Mean error: MPE; Erro
49、r shift: one third of the MPE in Table 4. After the test in 5.7.2, the pressure absorption tested in accordance with 5.3.2 a) shall not exceed 2,2 mbar. 5.7.2 Test Test a minimum of 6 meters. Where more than one installation orientation is specified by the manufacturer, test a minimum of 3 m in each orientation. The test equipment used for this test need not have absolute traceability provided that each meter is calibrated on equipment that does have such traceability prior to commencing the tes
