When you see this: click for more information

Variable Area Flowmeters (also known as Rotameters) offer cost effective yet accurate solutions for applications requiring visual indication of flow or flow rate.

Simple to Install and designed for small fluid flows (gas or liquids). They can be widely employed where the fluid is free of entrained solids and where the system provides locations for good visibility and proper mounting.

Available in a wide range of materials including low cost acrylic and specialist options such as PTFE for aggressive media or stainless steel for high temperature and pressure applications. We provide the option of a wide range of control and output options including control valves, set-point switches and analogue outputs.

Typical Application for variable area flow meters:Liquid flow meter or gas flow meter where high accuracy is not requiredMeasuring water and gas flow in plants or labsMonitoring chemical linesPurging instrument air lines (i.e. lines that use a valved meter)Monitoring filtration loadingMonitoring flow in material-blending applications (i.e. lines that use a valved meter)Monitor makeup water for food & beverage plants

Key Points for variable area flow meters:Variable area flow meters operate on the principle that the flow of the media will alter the position of a float in a tapered tube. The position of the float in the tapered tube is proportional to the volumetric flow rateTypical accuracy of variable area flow meters is ±3% full scaleA variable area flow meter normally has a turn down ratio in the region of 10:1A variable area flow meter normally requires vertical installation and a straight pipe run (minimum length of five times the diameter of the pipe) before the flow meters inlet

Advantages for variable area flow meters:Low costSimple to installEasy to use and virtually maintenance freeWide choice of materials including all PTFE for aggressive fluidsMany control options including control valves, set-point switches and analogue outputs

Disadvantages for variable area flow meters:Lower accuracy compared to many other flow meter technologiesAffected by pulsationSensitive to fluid changes such as viscosity, density and temperature