Differential pressure flowmeters

Differential pressure flowmeters are the most common flow meters. The extensive amounts of experience (the measuring technique has been around for 100 years) is reflected in the large number of appearances. The differential pressure flow meter measures the volume flow in gases, liquids and steam. They are particularly used in situations where high pressure, high temperature or a large diameter play a role. They are mainly found in the chemical, oil, gas and power industries.

When do you choose a differential pressure flowmeter?

In general you choose a differential pressure flow meter because this measuring principle is standardized in ISO 5167, which guarantees that this approach produces reliable measurement results.

The benefits of differential pressure flowmeters are generally:

• Relatively simple concept
• Can be made in many materials so that they can be used in many types of gases and liquids
• Suitable for low and high temperatures (ranging from -270 ° C to + 500 ° C)
• Minimum number of potential leak sources because they can be welded
• Measuring element made to measure for the application
• Can be used in large pipes (up to a few meters in diameter)
• Suitable for high pressures
• Suitable for gases, liquids and steam
• AGA certified, so can be used to measure natural gas
• Easy to maintain
• Low total cost of ownership

The appearance of differential pressure flowmeters differs depending on the flow element applied. Teesing supplies the following types:

In which cases do you choose another flow measurement method?

Differential pressure flow meters are less suitable in situations with:

• A very low flow (< 2 l/h)
• Small diameters (< 1”)
• Liquids with a high viscosity (> 50cP)
• Sanitary applications such as food

Of course you would also choose a different type of flowmeter if you have to measure without process interruption.

The supply of differential pressure meters by Teesing

The strength of Teesing lies in its ability to deliver relatively quickly. We keep this promise through our partnership with Seiko, who keep a large stock for us of a wide variety of metals. This Austrian brand exclusively produces differential pressure elements which gives them a lot of expertise about welding procedures and finishing.
Calibration
In addition, Seiko has its own calibration facility, NDT lab (non-destructive testing) and large stock of materials.
Certification
For many clients, certification is becoming increasingly important. Seiko is a leader in the field of documentation and certification, including PED certificates.
Conval calculations
Together with the client, our flow specialists make their own Conval calculations, so that the specifications and the achieved accuracy is well established in advance.
Pitot tubes
Another specialist in this field is PSI, of which we supply pitot tubes.

Practical examples

Since the 1990s, we have supplied differential pressure flow meters to Heineken, the Chemelot site, Shell, NAM, Vermillion, Stork Thermeq and Campina, among others.

At Campina, for instance, we measure feedwater in a steam boiler for application with an ISA nozzle flow meter and we measure steam with a venturi flow meter.

For NAM we measure wet natural gas at source on North Sea platforms with venturi flowmeters which are compensated for moisture. At TDC Kampen we measure air with tobacco particles with a cone flow meter.

At De Jong Combustion we measure natural gas flow to power plants.