Flow measurement and transmitters
Flow measurement is an operation carried out to measure the flow of fluids in a pipe using an instrument. Several flow-measuring instruments exist, which include the following:
- A differential pressure flow meter: This uses a pressure difference created by a sensing element (for example, an orifice plate or a Venturi tube) to determine the rate of a flow. A differential pressure transmitter has a high- and low-pressure port to which the high- and low-pressure side of the sensing element will be connected and it produces a standard signal of 4 to 20 mA that corresponds to the flow rate.
The following figure shows a Rosemount differential pressure transmitter:
Figure 12.12 – A Rosemount differential pressure transmitter (this file is licensed under the Creative Commons Attribution-Share Alike 4.0 International license)
- A velocity flow meter: This determines a flow rate by measuring the flow velocity...
