**Measuring the volume of a substance that has passed a particular point in a specified time period.**

The measurement of volumetric flow is called the volumetric flow rate, and this is defined as the amount of volume that will be transferred in a unit period of time i.e. Q or VĚ‡ = V / t.

Volumetric flow can be measured either directly using a volumetric flow meter, or indirectly by measuring the flow speed or a pressure drop created by a shaped obstacle. The volumetric flow rate can then be derived using mathematical formulas and other fixed parameters such as cross-sectional area, density etc…

There are many different units used for measuring volumetric flow rate. The type of substance, size of cross sectional area, flow speed, and geographic region, will all dictate the volume and time units which are the most convenient to use for a particular flow measurement. Popular volumetric flow rate units litres or gallons per second, minute or hour (L/s, L/m, L/h, gps, gpm, gph).

**Flow measurement products**

- 5 psi dp 0-10V out air pressure sensor for automation flow rate testing use on a 15psi line
- Vacuum testing controller and datalogger for pressure/flow measurement and regulating vacuum
- Water system peak demand pressure and flow data logger
- -200 to 200 Pa bi-directional range 4-20mA output dp pressure transmitter for venturi tube