# C075 – ISO 5167-1:1991 – Venturi Calculation

## Description

This calculation can be set to calculate the flow rate through a Venturi based metering system, the differential pressure setting of the metering system or the Venturi throat size to use for specified flowing conditions.

## References

ISO 5167-1:1991 – Measurement of fluid flow by means of pressure differential devices – Part 1: Orifice plates, nozzles and Venturi tubes inserted in circular cross-section conduits running full

ISO TR9464 – Guidelines for the use of ISO 5167

Kelton calculation reference C075

FLOCALC calculation reference F075

Kelton calculation C271 – ISO 5167 Venturi Mass Flow Calculation

Kelton calculation C273 – ISO 5167 Differential Pressure Calculations

Kelton calculation C274 – ISO 5167 Sizing Calculation

Kelton calculation C261 – Gas Flowrate Conversion from Qm

Kelton calculation C262 – Liquid Flowrate Conversion

## Options

### Solve for

• Flow rate
• Throat diameter
• Differential pressure

This option is used to select what kind of calculation the user wishes to implement.

The rest of the options that can be encountered in this calculation can be found in the calculations referenced above.

If solving for flow rate the options for this calculation are the same as for C271 ISO 5167 Venturi Calculations however the year of the standard will be set to 1991.

When solving for throat diameter or differential pressure the options available will be the same as C274: ISO 5167 Sizing Calculation or C273: ISO 5167 Differential Pressure Calculation respectively with the version of the standard set to 1991 and the meter type set to Venturi.

## Calculation

### Mass Flow Rate

The mass flow rate is calculated using the formula shown in C271. Further flow rate outputs, if required, are calculated using one of the flow rate converters using this value of mass flow rate.

### Throat Diameter

The Venturi throat diameter is calculated according to the process described in C274.

### Differential Pressure

The differential pressure is solved as described in C273.

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