ISO 5167 ensures accurate measurement of fluid flow. It defines the methods and instruments for measuring fluid flow by means of depressurizing devices inserted in loaded pipes of circular cross-section. The standard provides essential guidelines for the use of depressurizing devices such as diaphragms, nozzles and Venturi tubes.
ISO 5167 consists of six parts, each dealing with a specific aspect of flow measurement.
It covers general principles, orifice plates, nozzles, Venturi tubes, measuring cones and wedge flowmeters. These devices are inserted into a loaded pipe to determine fluid flow.
The2022 edition of ISO 5167 brings important updates.
It incorporates new data and improved methods for calculating flow rate and associated uncertainty. These changes are designed to ensure more accurate and reliable measurements in a wide range of industrial applications.
ISO 5167-1 establishes the basic principles for measuring fluid flow by means of depressors inserted in loaded pipes of circular cross-section. It applies to depressors inserted in loaded pipes of circular cross-section. This section defines essential terms and symbols. It also sets out the general requirements for the use of these measuring devices.
The devices concerned include orifice plates, nozzles, Venturi tubes, cones and wedge flowmeters. All these instruments are designed for installation in solid pipes. The standard covers the geometry of the devices and their method of use. It specifies the installation and operating conditions to be met to obtain reliable measurements. One aspect covered is the calculation of flow rate andassociated uncertainty. The standard provides the information needed to perform these calculations accurately.
Clarifications have been made in Part 1 concerning the combination of standard uncertainties and the incorporation of practical examples. Internal diagnostics of pressure transmitters and the use of multiple transmitters to improve accuracy have been introduced. In addition, the flow measurement range has been extended, offering a ratio of 2:1 to around 11:1 thanks to improved pressure transmitters.
ISO 5167-2 deals with diaphragm flow measurement. It sets out the general principles for measuring and calculating fluid flow in a circular pipe under load. The standard requires devices to be inserted into a filled circular-section pipe. It provides detailed information on flow calculation and associated uncertainty.
Modifications apportées dans la version 2022 : L’épaisseur maximale des bords des diaphragmes, lorsque le rapport β<0,2\beta < 0,2β<0,2, a été clarifiée. Cette modification vise à assurer une plus grande précision pour les petits diaphragmes, en particulier pour des rapports de diamètre β\betaβ faibles.
ISO 5167-3 describes nozzles and venturi nozzles used to measure fluid flow. These devices are inserted into loaded pipes with a circular cross-section. This standard applies to subsonic flows of single-phase fluids. It specifies pipe diameter and Reynolds number limits for the use of these devices. Nozzles and Venturi nozzles operate on the pressure-difference principle. The fluid passes through a narrowed cross-section, creating a measurable pressure difference.
Main features :
The standard details the datasheet technical specifications for the manufacture and installation of these devices.
It also provides equations for calculating flow from differential pressure measurements.
Changes made in version 2022: Updates have been made to threaded throat nozzles, improving discharge coefficients and reducing overall measurement uncertainty.
ISO 5167-4 defines datasheet for Venturi tubes used in fluid flow measurement. Venturi tubes operate on the pressure difference principle. They consist of a converging section, a neck and a diverging section. The standard covers several important aspects:
Venturi tube flowmeters offer several advantages:
Changes made in version 2022: Clarifications have been made concerning the straight lengths required upstream, as well as the integration of new experimental data for machined Venturi tubes. The expanded uncertainty of discharge coefficients is now 1.8%.
ISO 5167-5 defines datasheet for measuring cones used in fluid flow measurement. These devices are inserted into loaded pipes with a circular cross-section. Measuring cones are part of depressurizing devices. They create a pressure difference to measure flow. Their unique design enables precise measurement under a wide range of flow conditions.
Changes made in version 2022: Two corrections have been made to version 2016. These corrections include adjustments in the schematic key to ensure consistency with the drawings and datasheet of the internal angles of the truncated cone.
ISO 5167-6 covers wedge-type flowmeters used to measure the flow of fluids in a pipe. The standard specifies the geometry and operating conditions of these devices. It defines application limits in terms of pipe diameter, roughness and Reynolds number. It provides the information needed to calculate flow and its uncertainty.
Changes made in version 2022: A correction has been made to Appendix B concerning the definition of the Kd2K_d^2Kd2 coefficient, as well as additional clarifications on the uncertainty relating to expansibility.
ISO 5167 recommends regular calibration of measuring instruments. The process involves comparing the instrument's measurements with known reference values.
Calibration must be carried out under conditions similar to those of actual use. The standard provides guidelines on frequency and appropriate calibration methods.
The current version of ISO 5167 2022 comprises six separate parts. It has been updated in 2022 to include new device types such as measuring cones and wedge flowmeters.
Recent editions incorporate technological advances and improvements based on industry feedback. They also provide more detailed instructions for use and installation.
The choice of an ISO 5167-compliant measuring device depends on a number of factors. The nature of the fluid, the expected flow rate and the flow conditions are critical parameters.
Accuracy requirements, installation constraints and maintenance costs also influence selection. The standard provides guidelines for selecting the most appropriate device according to these criteria.
