Cole-Parmer offer an extensive range of variable area flow meters for both liquid and gas applications. Cole-Parmer's variable area flow meters are simple to install and offer cost effective solutions for applications requiring visual indication of flow or flow rate. Cole-Parmer offers variable area flow meters for measuring liquids flow from 0.0002 ml/min to over 400 LPM and for gases from 0.02 ml/min to over 700 m³/hour.

Cole-Parmer's variable area flow meters are 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. Many of our variable area flowmeters come with a wide range of control and output options including control valves, set-point switches and analogue outputs.

To find the right flow meter for your application use Cole-Parmer's on-line flow meter quick search. Alternatively contact our Application Specialists for free technical support and let us bring over 50 years of flow control experience to help solve your application needs.

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 rate
• Typical accuracy of variable area flow meters is ±3% full scale
• A variable area flow meter normally has a turn down ratio in the region of 10:1
• A 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 cost
• Simple to install
• Easy to use and virtually maintenance free
• Wide choice of materials including all PTFE for aggressive fluids
• Many 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 technologies
• Affected by pulsation
• Sensitive to fluid changes such as viscosity, density and temperature

Typical Application for variable area flow meters

• Liquid flow meter or gas flow meter where high accuracy is not required
• Measuring water and gas flow in plants or labs
• Monitoring chemical lines
• Purging instrument air lines (i.e. lines that use a valved meter)
• Monitoring filtration loading
• Monitoring flow in material-blending applications (i.e. lines that use a valved meter)
• Monitor makeup water for food & beverage plants