Differential pressure flow meter: SITRANS F O

Differential pressure measurement is a universal flow measurement for liquids, gases and vapors. Differential pressure flow meter always provide accurate results even with large bores, high temperature and extreme pressure. 

Industry Mall

Select and order

Primary differential pressure devices, like SITRANS F O orifice, are standardized mechanical flow sensors according DIN EN ISO 5167 which are used for volume and mass flow measurement. The SITRANS F O orifice are suitable for non-corrosive and corrosive gases, vapors and liquids; permissible operating temperature -60 to +570 °C. The created differential pressue will be converted with the help of a differential pressure transmitter SITRANS P delta P into a proportional flow signal. For calculation of the SITRANS F O orifice to DIN EN ISO 5167 is an completed filled out questionnaire necessary.


  • Orifice flowmeters are very robust and can be used in a wide range of nominal diameters

  • Suitable for wide ranges of temperature and pressure

  • No calibration required as the process is standardized

  • The electronics required in addition can be used over a long distance from the measuring location

  • The differential pressure measurement is well known and has a large installed base


Primaries / Differential pressure devices

Mounting between flanges with welded connections 
Orifice with annular chamber or single tappings
Metering pipe with orifice plate, annular chamber or single tappings

Flanged orifice plate with flange tappings
Venturi nozzle
Classical venturi 


Nominal Sizes
From DN 10 to DN 1000
From ½ inch to 40 inches
Temperature Range
From -60 to 570 °C
From -76 to 1058 °F
Operating Pressure
Max. 315 bar
Max. 4570 psi
Process Connections
Thread G½ and ½-14 NPT
cutting ring
Orifice Material
1.7335, 1.4404. 1.4571, 1.4576 and further materials on request

Differential pressure flow meter application examples: Power stations, Petrochemical industry, Chemical industry 

Download, Support, Services

Find download, support and services for Siemens Process Instrumentation.

The fastest way to the experts

Proposed solutions for your queries and direct access to our experts in Technical Support.

Service offers

To remain competitive, companies in industry must ensure – and ideally increase – the availability and productivity of machines and plants. As your partner, we offer a unique range of services and support based on our extensive technology and industry expertise.

Service catalog

As your partner, we offer a unique range of services and support based on our extensive technology and industry expertise. With our offerings, you can expect a high degree of reliability and a successful digital future for your company.

Well trained for excellent handling

Receive standardized or individual expertise directly from the manufacturer – with training centers in more than 60 countries.

Safety integrated

Safety is key in the process industries. A failure in instruments relevant for safety may have serious implications for humans, the process and the environment. Therefore, a wide range of our process instruments come with on-board safety features for maximum risk reduction.


Any medium, any pipe size - SITRANS F has you covered

Monitoring your processes with accurate flow measurement leads to higher transparency, improved productivity - and a better bottom line. To optimize every operation, Siemens offers a comprehensive selection of flow sensors and transmitters as well as complete flow systems across all technologies, including electromagnetic, Coriolis, ultrasonic, vortex, variable area, rotary piston and differential pressure.

Your direct line to Siemens

Contact your regional partner