NF EN ISO 5167-1

Dans la série des normes X 10-1... qui concerne la mesure du débit des fluides dans les conduites fermées, la présente norme traite de la forme et des conditions d'emploi des différents appareils déprimogènes, et donne également les informations relatives au calcul du débit et des incertitudes associées.

<p>ISO 5167-1:2003 defines terms and symbols and establishes the general principles for methods of measurement and computation of the flowrate of fluid flowing in a conduit by means of pressure differential devices (orifice plates, nozzles and Venturi tubes) when they are inserted into a circular cross-section conduit running full. </p> <p>ISO 5167-1:2003 also specifies the general requirements for methods of measurement, installation and determination of the uncertainty of the measurement of flowrate. It also defines the general specified limits of pipe size and Reynolds number for which these pressure differential devices are to be used.</p> <p>ISO 5167 (all parts) is applicable only to flow that remains subsonic throughout the measuring section and where the fluid can be considered as single-phase. It is not applicable to the measurement of pulsating flow. </p>

<p>ISO 5167-2:2003 specifies the geometry and method of use (installation and operating conditions) of orifice plates when they are inserted in a conduit running full to determine the flow-rate of the fluid flowing in the conduit.</p> <p>It also provides background information for calculating the flow-rate and is applicable in conjunction with the requirements given in ISO 5167-1.</p> <p>ISO 5167-2:2003 is applicable to primary devices having an orifice plate used with flange pressure tappings, or with corner pressure tappings, or with <i>D</i> and <i>D</i>/2 pressure tappings. Other pressure tappings such as vena contracta and pipe tappings have been used with orifice plates but are not covered by ISO 5167-2:2003. </p> <p>ISO 5167-2:2003 is applicable only to a flow which remains subsonic throughout the measuring section and where the fluid can be considered as single phase. It is not applicable to the measurement of pulsating flow. It does not cover the use of orifice plates in pipe sizes less than 50 mm or more than 1 000 mm, or for pipe Reynolds numbers below 5 000.</p>

<p>ISO 5167-3:2003 specifies the geometry and method of use (installation and operating conditions) of nozzles and Venturi nozzles when they are inserted in a conduit running full to determine the flow-rate of the fluid flowing in the conduit.</p> <p>ISO 5167-3:2003 also provides background information for calculating the flow-rate and is applicable in conjunction with the requirements given in ISO 5167-1.</p> <p>ISO 5167-3:2003 is applicable to nozzles and Venturi nozzles in which the flow remains subsonic throughout the measuring section and where the fluid can be considered as single-phase. In addition, each of the devices can only be used within specified limits of pipe size and Reynolds number. It is not applicable to the measurement of pulsating flow. It does not cover the use of nozzles and Venturi nozzles in pipe sizes less than 50 mm or more than 630 mm, or for pipe Reynolds numbers below 10 000.</p> <p>ISO 5167-3:2003 deals with two types of standard nozzles, the ISA 1932 nozzle and the long radius nozzle, as well as the Venturi nozzle. </p> <p>The two types of standard nozzle are fundamentally different and are described separately in ISO 5167-3:2003. The Venturi nozzle has the same upstream face as the ISA 1932 nozzle, but has a divergent section and, therefore, a different location for the downstream pressure tappings, and is described separately. This design has a lower pressure loss than a similar nozzle. For both of these nozzles and for the Venturi nozzle direct calibration experiments have been made, sufficient in number, spread and quality to enable coherent systems of application to be based on their results and coefficients to be given with certain predictable limits of uncertainty.</p>

<p>ISO 5167-4:2003 specifies the geometry and method of use (installation and operating conditions) of Venturi tubes when they are inserted in a conduit running full to determine the flowrate of the fluid flowing in the conduit. </p> <p>ISO 5167-4:2003 also provides background information for calculating the flow-rate and is applicable in conjunction with the requirements given in ISO 5167-1.</p> <p>ISO 5167-4:2003 is applicable only to Venturi tubes in which the flow remains subsonic throughout the measuring section and where the fluid can be considered as single-phase. In addition, each of these devices can only be used within specified limits of pipe size, roughness, diameter ratio and Reynolds number. ISO 5167-4:2003 is not applicable to the measurement of pulsating flow. It does not cover the use of Venturi tubes in pipes sized less than 50 mm or more than 1 200 mm, or for where the pipe Reynolds numbers are below 20 000.</p> <p>ISO 5167-4:2003 deals with the three types of classical Venturi tubes: cast, machined and rough welded sheet-iron.</p> <p>A Venturi tube is a device which consists of a convergent inlet connected to a cylindrical throat which is in turn connected to a conical expanding section called the "divergent". The differences between the values of the uncertainty of the discharge coefficient for the three types of classical Venturi tube show, on the one hand, the number of results available for each type of classical Venturi tube and, on the other hand, the more or less precise definition of the geometric profile. The values are based on data collected many years ago. Venturi nozzles (and other nozzles) are dealt with in ISO 5167-3.</p>