Flow sensors can be purchased at any reputable distributor, such as RS Components and are used for:

  • oil and gas 
  • solvents and chemicals
  • drugs 
  • industrial coolants 
  • steam 


Which type of flow sensor is right for my business?

Water flow sensor

As the water passes through the sensor, the turbine is rotated sending a signal to the wire coil attached.  The speed of the water passing through alters the speed the paddle or turbine is turned, providing a measurement of water flow. 

Magnetic-Inductive Volumetric Flow Meters

As conductive liquid flows through the magnetic field, a voltage signal is created, with the signal increasing with the speed of the flow. 

Thermal Mass Flow Sensor 

Capillary Thermal Mass flow meter

Gas diverted through a narrow tube is measured via signals between two PRTD coils attached to the tube. The difference in the signals travelling either with or against the current is directly proportional to the flow, providing a measurement of the mass of the gas flow.

Immersible Thermal Mas flow meter. 

A temperature sensor which measures the internal gas temperature and a velocity sensor are inserted through the piping into the flow with a constant differential maintained between each.  The heat from the velocity sensor transfers to the gas molecules as they pass.  The electrical wattage that is required to reheat the sensor is proportional to the mass flow rate providing an accurate measurement of total gas mass flow rate.   

Transit Time flow measurement 

A transducer emits an ultrasonic beam into the passing fluid which is reflected off present solid particles or air bubbles to the receiving transducer.  The frequency that the reflected beam is received measures the flow, as the frequency shift is linearly proportional to the flow rate.  

To measure flow that does not have bubbles or solid particles, the two transducers are placed on each side of the pipe diagonally opposite. The speed of the beam return changes according to whether the stream is going with or against the flow.  If the flow has stopped, the beam will travel at the same speed in both directions.  


Vortext shedding flow sensor. 

A blocking body inside the pipe causes vortices to form which then create zones of low and high pressure known as the Karmen Vortex Street.  A mechanical sensor detects changes in the pressure of the liquid measuring the flow by counting the vortices as they pass.  The difference between the vortices corresponds with a defined measurement of the fluid.


Choosing your flow sensor 

Ask your supplier about the most efficient type of flow sensor that will suit the velocity, viscosity, conductivity and  purity of your liquid or gas flow.  Higher quality flow sensors provide reliable data which will ensure that any issues with the liquid flow are immediately detected and preventative maintenance applied.  Discuss your needs with an expert to get the most accurate and efficient use out of your flow sensors. 


By Jim O Brien/CEO

CEO and expert in transport and Mobile tech. A fan 20 years, mobile consultant, Nokia Mobile expert, Former Nokia/Microsoft VIP,Multiple forum tech supporter with worldwide top ranking,Working in the background on mobile technology, Weekly radio show, Featured on the RTE consumer show, Cavan TV and on TRT WORLD. Award winning Technology reviewer and blogger. Security and logisitcs Professional.