Paddle wheel

Paddle wheel flow meters can operate as both in-line flow meters or insertion style flow meters.

The operating principle is similar to that of a turbine flow meter, whereby flow within the pipework allows a wheel with paddle to rotate freely with the flow of the fluid. The wheel is fixed and the faster the flow rate of the fluid, the faster the paddle wheel spins. The speed at which the wheel rotates is detected and this is converted into a volumetric flow rate.

The difference is that a paddle wheel flow meter is not directly in all of the flow path, whereas with a turbine flow meter the turbine blades will cover the majority of the cross sectional flow path.

Paddle wheel flow meters have many advantages which include:

• Fast response times
• Easy installation, operation and maintenance
• Economical price with a low cost of ownership
• Low pressure drop

Paddle wheel flow meters also have some limitations which are listed below:

• Some applications will require straight pipework before and after the flow meter
• The pipe work must be full at all times
• Can only be used with liquids, ideally low viscous liquids.