control variables

1. What are the primary control variables?

Temperature

Pressure

Flow

The level is excluded, which is not a primary control variable because the level is controlled by manipulating flow to tank

 flow meters

1. What are the different flow meters?

Based on the working principle, there are 5 types of flow meters:

Differential pressure(DP) flow meter:- example: Orifice plate, Venturi meter, Flow nozzle, Rotameter.

Velocity Flowmeter:- Electromagnetic flowmeter, Ultrasonic flowmeter, Turbine flowmeter, Paddlewheel flow meter.

Positive displacement flowmeter:- Nutating disk, Rotary vane, Gear, Diaphragm flowmeter.

Mass flowmeter:- Coriolis flowmeter, Thermal dispersion meter,

2. What is Flow compensation?

In steam or gas flow measurement, the density of the steam or gas changes as pressure and temperature change. This change in density can affect the accuracy of the measured flow rate if it is uncompensated. Temperature, pressure compensated flow control is a mathematically adjusted flow control with one or more additional variables.

3. What is Ultrasonic flowmeter?

Ultrasonic flowmeters pass high-frequency sound wave to the fluid path to measure the fluid velocity. The ultrasonic method uses the change in the moving fluid’s propagation time. There are two main types of ultrasonic flowmeters: Doppler and form of transit time.