Paddlewheel Flow Meters: Working Principle and Where to Use?

If you are curious to know what paddlewheel flow meters are, then you need to read this post to the end because buying a suitable paddlewheel flow meter depends on how well you know it. In many industries, tools are used to make work easier. In the flow measurement world, for instance, paddlewheel flow meters are used to obtain a liquid or fluid flow rate. Paddlewheel is among the most cost-effective flow meters in the world today. Let’s look at a particular one called the paddlewheel flow meter and what it has to offer.

What is a Paddlewheel Flow Meter 

In the flow measurement sector, machinery and tools are designed to cater to a particular application. For example, a flow meter is used to measure the flow of fluid that runs through a pipe. They are cost-effective because they are simple to use and install. A paddle wheel flow meter has several components found inside it. One that plays a vital role is the rotors. What usually influences the selection process of a paddle wheel include the installation process, the application requirements, the fluid capacity and pressure flowing through the pipe, and more. The material used to make the flow rate also determines the cost and application you are going for. Before exploring the paddlewheel flow meter, let’s look at the several flow meter categories used in various industries. 

  • Mass flow meters 
  • Open channel flow meters
  • Differential pressure flow meters 
  • Positive displacement flow meters
  • Velocity flow meters

You need to know that the paddlewheel flow meter is grouped among the flow meters that belong to the velocity flow meter category. Volumetric flow rate is directly proportional to liquid velocity. If you need to know how a paddlewheel flow meter works, you need to know about its working principle. Every flow meter has a working principle that acts as a guide when measuring flow. When it comes to the paddlewheel flow meter, there will be a reduction in its sensitivity when Reynold’s number of fluids falls below 10000. 

Other flow meters that belong to the same category as the paddlewheel flow meter include the turbine flow meter, electromagnetic flow meters, ultrasonic flow meters, and vortex shedding flow meter.

How the Paddle Wheel Flow Meter Measures Flow Rate 

There are two mechanical groups that fall into paddlewheel meters. One of them is the tangential-flow paddlewheel flow meter, and the other one is known as the axis-flow paddlewheel flow meter. The structure that the axis-flow is built-in is a windmill. The tangential-flow paddle wheel flow meter is built like a water mill. Magnets are fitted on the axis and paddle blades. This allows this type of flow meter to transform pulses into signals. The movement of water through the flow meter will force the paddle to rotate or spin. When the water is moving at high speeds, the paddle will spin rapidly. If the pressure of the water flowing through the pipe is low, the paddle will spin slowly, making it directly proportional to hit flow. The pipeline before and after the paddlewheel needs you to be straight. 

Since the paddle wheel has moving parts inside, it has to be well taken care of. You should not use it with slurry liquids that may end up jamming the flow meter. Accumulated dirt and debris may also cause the paddlewheel flow meter to give inaccurate readings. 


The low cost of a paddlewheel meter is what attracts most people to paddlewheel flow meters. It is also easy to install and maintain. You can also depend on the paddlewheel flow meter to give very accurate readings. If you are looking for a flow meter that won’t disappoint, then the paddlewheel will work out just fine, especially if you are using clear water. 

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