Table of Contents

1 Scope
2 Normative references
3 Definitions
4 Symbols and subscripts
4.1 Symbols
4.2 Subscripts
5 Principle of the method of measurement and
computation
5.1 Principle of the method of measurement
5.2 Method of determination of the diameter ratio
of the selected standard primary device
5.3 Computation of rate of flow
5.4 Determination of density
6 General requirements for the measurements
6.1 Primary device
6.2 Nature of the fluid
6.3 Flow conditions
7 Installation requirements
7.1 General
7.2 Minimum upstream and downstream straight
lengths required for installation between
various fittings and the primary device
7.3 Flow conditioners
7.4 General requirements for flow conditions at
the primary device
7.5 Additional specific installation requirements
for orifice plates, nozzles and Venturi nozzles
7.6 Additional specific installation requirements
for classical Venturi tubes
8 Orifice plates
8.1 Description
8.2 Pressure tappings
8.3 Coefficients and corresponding uncertainties
of orifice plates
8.4 Pressure loss, ??
9 Nozzles
9.1 ISA 1932 nozzle
9.2 Long radius nozzles
10 Venturi tubes
10.1 Classical Venturi tubes
10.2 Venturi nozzle
11 Uncertainties on the measurement of flow-rate
11.1 Definition of uncertainty
11.2 Practical computation of the uncertainty
Annexes
A Tables of discharge coefficients and
expansibility [expansion]factors
B Classical Venturi tubes used outside the scope of
this part of ISO 5167
C Pressure loss in a classical Venturi tube
D Iterative computations
E Examples of values of the pipe wall uniform
equivalent roughness, k

Abstract

Specifies the geometry and method of use for orifice plates, nozzles and Venturi tubes for the determination of fluid flow rate in a closed conduit running full. Information for the calculating of a flow rate and its associated uncertainty is included. The Standard applies to conduits with diameters within the range 50 mm to 1200 mm inclusive. It is identical with and has been reproduced from ISO 5167-1:1991.

Scope

This part of ISO 5167 specifies the geometry and method of use (installation and operating conditions) of orifice plates, nozzles and Venturi tubes when they are inserted in a conduit running full to determine the flow-rate of the fluid flowing in the conduit. It also gives necessary information for calculating the flow-rate and its associated uncertainty. It applies only to pressure differential devices in which the flow remains subsonic throughout the measuring section and is steady or varies only slowly with time 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 and Reynolds number. Thus this part of ISO 5167 cannot be used for pipe sizes less than 50 mm or more than 1 200 mm or for pipe Reynolds numbers below 3 150. It deals with devices for which 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. The devices introduced into the pipe are called "primary devices". The term primary device also includes the pressure tappings. All other instruments or devices required for the measurement are known as "secondary devices". This part of ISO 5167 covers primary devices; secondary devices 1)will be mentioned only occasionally.

General Product Information

Published
Document Type	Standard
Status	Current
Publisher	Standards Australia
Pages
ISBN
Committee	CE-024