Flow Measurement

Table of Contents

Flow measurement is the oldest of all measurement process variables in the field of instrumentation. It is designed to determine the proportion and quantity of material flowing in or out of a process. For the purpose of cost accounting, such measurements are often required for steam, water and gas services. Without flow measurement, plant material balancing, quality control and even the operation of any continuous process would be nearly impossible.

There are three types of flow

  1. Laminar (Viscous) Flow
  2. Turbulent Flow

Laminar (Viscous) Flow:

Let a liquid flow slowly and steadily over a fixed horizontal surface, such that a layer of liquid moves parallel to it, with their velocity increasing uniformly from one layer to the next. The velocity is maximum at the free surface of the liquid. This type of fluid flow in which its layers slide over each other without mixing is called laminar flow.

Turbulent flow

If the liquid is pushed into the tube too fast, the flow may become turbulent. In matter, the velocities of different particles pass though the same point may vary and change erratically with time. The water speed in the high falls is a fast flowing river which is generally turbulent.

Flow Unit

  1. Liquid flow rate = liter / hr, M 3  / h r
  2. Mass flow rate = kg / hr, lb / hr, UK ton / hr

Type of measurement

1.Head type measurements

  1. Orifice plates Click Here
  2. Venturi meters Click Here
  3. Flow nozzles Click Here
  4. Pitots tubes Click Here
  5. Annubars Click Here

2.Area type measurements

  1. Glass tube Rota meter Click Here
  2. Metal tube Rota meter Click Here

3.Mass Flow meters Click Here

4.Turbine Flow meters Click Here

5.Magnetic Flow meters Click Here

6.Vortex Flow meters Click Here

7.Coriolis Flow meters Click Here

8.Oval Gear meters Click Here

9.Ultra Sonic Flow meters Click Here

10.Open Channel meters Click Here

  1. Rectangular Type Click Here
  2. “V” notch Type Click Here
  3. Trapezoidal Type Click Here


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