Measuring liquid flow is a key requirement in many industrial plants. In some operations, the ability to accurately measure traffic is very important, and it can determine profit or loss. In other cases, inaccurate flow measurements or failure to make measurements can lead to serious (or even catastrophic) results.
For most liquid flow measurement instruments, flow rate is inferred by measuring changes in the velocity or kinetic energy of a liquid. The flow rate depends on the pressure difference that forces the liquid through the pipe. Since the cross-sectional area of the pipe is known and remains constant, the average flow rate is an indicator of the flow rate. In this case, the basic relationship for determining the flow rate of the liquid is
Q = V x A
Q = The flow of liquid through the pipe
V = average traffic
A = pipe cross-sectional area
Other factors that affect the flow rate of a liquid include the viscosity and density of the liquid, as well as the frictional force of the liquid when it comes into contact with the pipe.
Liquid flow can be measured directly using a positive displacement flow meter. These units divide the liquid into specific increments and continue to move. The total flow rate is the accumulation of measurement increments and can be calculated mechanically or electronically.