A flow meter is used to measure the flow rate of liquid or gas moving through a pipe. Flow meters have quite a few other monikers:
- Flow gauge
- Flow indicator
- Liquid meter
- Water meter
Their applications are dependent on the particular industry, but their main function is constant; measuring flow.
Do you need a precision flow meter?
Not necessarily. A precision flow meter is only needed to provide accurate monitoring. There are industrial applications that need a precise calculation of quantity, for instance, the exact servo-valve development for aerospace industries. If you are not in such an industry, you can give the precision flow meter a pass.
Types of flow meters
- Positive Displacement – This one is also known as a volumetric flow meter or PD flow meter. All max machinery flow meters are positive displacement flow meters.
- Displacement/volumetric
- Mass
- Velocity
- Electromagnetic
- Ultrasonic
- Turbine
- Vortex Shedding and sonar
- Targetand vane
- Variable area and rotameter
- Orifice plate
- Open channel
- Flow Nozzle
- Laminar
- Venturi
- Pitot tube
Which type is the best?
Since the different types are used different applications, you cannot have one that surpasses them all. What is important is knowing exactly what application you need the meter for. You need to know the following before you choose a meter:
- The liquid or gas that is to be measured
- What are the maximum and minimum flow rates?
- What is the fluid temperature and viscosity?
- Is the fluid compatible with the construction materials?
- How much pressure is allowed?
- The location where the meter will be mounted
- Whether the flow is continuous or sporadic
When you know what you need the meter for, you have a better chance of crossing off what you do not need. Then you are closer to finding the flow meters you need for the particular applications you need them for.
Air flow meters
Air flows just like liquid does and it is also measured with meters. An air flow meter measures the volume of air flowing through the tube. The mass of air is measured per unit time as it passes through the flow meter. Air flow meters are applicable in automobiles. They measure the volume of air that flows into the internal combustible engine. Modern diesel engines which are electronically controlled need an air flow meter. This is the only way the air intake in the combustible engines can be determined.
Types of air flow meters
- The vane air flow meter
- The hot wire or hot film mass meters
The vane type measures air volume while hot ones measure the mass of air flow. The flap-type meter has a spring which restores the flap to its home position.
Air flow meters are also applicable in industrial environments in manufacturing processes.
Air flow meters are to be chosen wisely since their applications are so diverse. Therefore, getting advice from the experts would be a good step so that you are sure you are getting the right meter for the right application.
