EN 1267 pdf free download
EN 1267 pdf free download.Ventiler – Maling af gennemstromnings- modstand med vand som provemedie.
4 Test installation 4.1 General The test installation(s) shall be in accordance with figure 1. The position of the components outside the frame shall be chosen by the laboratory. For angle valves (1b) the valve under test and test length Ls may be arranged to lay in a horizontal or vertical plane. For multi end port valves, additional test tubes of the same type shall be used in the same manner. 4.2 Test tubes The lengths of the test tubes and the position of the pressure tapping points shall be in accordance with figure 1. The lengths are measured from the ends of the test tubes. If the test installation has upstream, two elbows in series and in different planes, it is necessary to make L1 longer than 10 D unless a flow straightener is installed before the upstream test tube. If a flow straightener is used, the length L1 may be shorter than 10 D provided the conditions in 5.1. are satisfied. Further details of flow straighteners shall be found in clause 6 of Iso 7194:1983. The test tubes shall be straight, the ends shall be cut square and deburred, and the internal surfaces shall be clean and without obstructions when inspected visually. The internal diameters are chosen by the valve manufacturer if not stated in relevant valve, product or performance standard. For valves with low ζ5-value, the results obtained will be affected by the internal diameter of the test tube. Therefore, it is necessary to record the actual internal diameter of the test tube (see 7.2).Note When new test tubes are made, it is recommended to make them in accordance with annex A. The number of holes for the pressure tappings shall be chosen by the laboratory. At each pressure point, there may be one, two or four holes, or a slit provided excentricity is avoided. Four tapping holes are recommended for DN > 300.The diameters of the pressure tapping holes shall be in accordance with table 1 and the length shall be at least twice the diameter. The edge of the pressure tapping hole at the internal surface of the test tube shall be sharp and free from burrs. The axis of the pressure tapping hole shall intersect the axis of the test tube and be at right angle to it, with a maximum deviation of 5。. Connecting tubes between the pressure tappings and pressure measuring devices shall have an internal diameter of at least twice the diameter of the tapping holes. In order to avoid dirt accumulation, no tapping hole shall be located at the bottom of the CrOSs section.4.3 Measuring equipments The pressure loss shall be measured with a dfterential pressure device. Devices or methods which are known by calibration or references to other standards to result in a measurement with a systematic uncertainty not exceeding the maximum permissible values shall be used. The maximum values of systematic uncertainties alwed for each kind of measurement by this standard are : – upstream pressure, dfferential pressure and flow rate measurements:土2%; – temperature measurements:土1°C. 4.4 Test fluid Test fluid shall be water with a temperature between 5。C and 40 oC. 5 Test procedure 5.1 Test conditions 5.1.1 Permissible fluctuations in measurements For each quantity to be measured, the prmissible amplitude of reading fluctuations is given in tables 2 and 3. If fluctuations of greater amplitude are present, measurements may be carried out by providing a damping device. The istallation of the damping device shall not aftect the accuracy of the readings: use shall be made of symmetrical and linear damping device.EN 1267 pdf download.
