--- title: Guide to Variable Area Flow Meters description: Looking to learn more about variable area flow meters? Read this guide to learn the features, uses, and benefits of variable area flow meters. image: https://blog.techstar.com/hubfs/RAKD-1-198x300.jpg --- [![Teckstar](https://blog.techstar.com/hubfs/header-logo-1.png)](http://techstar.com/) [SPEAK TO AN EXPERT](https://techstar.com/asktechstar/?__hstc=233546881.94308a3d6ad9d040c1c30bf75699981b.1700673178130.1709582481954.1709637461889.239&__hssc=233546881.1.1709637461889&__hsfp=541284016) [ONLINE STORE](https://store.techstar.com/?__hstc=233546881.94308a3d6ad9d040c1c30bf75699981b.1700673178130.1709582481954.1709637461889.239&__hssc=233546881.1.1709637461889&__hsfp=541284016) - OUR COMPANY - [Sales Coverage](https://techstar.com/locations) - [Office Locations](https://techstar.com/locations#offices) - [Ask An Expert](https://techstar.com/asktechstar/) - [Who We Are](https://techstar.com/who-we-are) - [Industries](https://techstar.com/industries) - [Tale of the Goat](https://techstar.com/about-us/the-tale-of-the-pale-goat/) - [STAR Scholarship](https://techstar.com/scholarship/) - 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[SERVICE](https://techstar.com/extra-manpower/) - [TRAINING](https://techstar.com/training/) - [Technical Courses](https://techstar.com/category/courses/) - [Hands On Application](https://techstar.com/theunit/) - [Custom Sessions](https://techstar.com/custom-sessions/) - [Distance Learning](https://info.techstar.com/t3-library-distance-learning) - RESOURCES - [Blog](https://blog.techstar.com/news) - [Calendar of Events](https://techstar.com/category/courses/) - [Knowledge Center](https://info.techstar.com/resources) - [View Line Card](https://techstar.com/wp-content/uploads/2026/06/TS-All-Territory-Line-Card-LR-copy.pdf) - [CONTACT US](https://techstar.com/asktechstar/)   **TECHSTAR** **BLOG** # Variable Area Flow Meter: Features, Uses, Benefits Posted by [TechStar](https://blog.techstar.com/news/author/twineng) on Dec 14, 2022, 6:00:00 AM - [Tweet](https://twitter.com/share) If you are looking for a flow meter that provides easy readings of flow rate, consider the [variable area flow meter](https://techstar.com/solutions/flow-solutions/). This device measures liquids, steam, and gas in a variety of conditions and environments. In this guide, we define variable area flow meters, along with the working principle, features, application, and benefits.  ## What is a Variable Area Flow Meter? Variable area flow meters are also commonly referred to as rotameters.  Variable Area Flow Meters are direct acting measurement indicating devices that do not require any power supply.  They are one of the oldest types of devices used to measure flow.  Variable area flow meters are known for their flexibility and reliability across a multitude of liquid and gas applications. These meters are  available in various materials designed to suit a large range of mediums and applications. Additionally, custom variable area flow meters are available  for unique applications.  ## How Does a Variable Area Flow Meter Work? Variable area flow meters have a cone, float, scale, and process connection. The operating principle behind the design is simple, the float rises inside a cone-shaped tube as  the flow increases. The position of the float corresponds  to the position on the scale indicating the flow rate.  ## Variable Area Flow Meter Features Variable area flow meters have a number of features, such as:  ### Indicator Depending on a glass or metal meter,  they all have indicators  that display the measurement. The indicator is commonly available in stainless steel or aluminum if metal meters are chosen or the scale is printed directly glass tube meter.  The indicators are typically red and as the process media increases or decreased the measurement is indicated on the meter.  ### Limited Switches (optional) Devices equipped with maximum and minimum limit switches, this option is  reflected in the flow scale.  ### Electrical or Analog Components Although  variable area flow meters are  used  entirely  as mechanical devices , power can be added as an option, along with an electronic output.   ### Float Damping System Variable area flow meters designed for gas applications have a float damping system to avoid bouncing and wearing down the float. The float damping system reduces the maintenance requirements of the device.  ## Variable Area Flow Meter Applications Variable area flow meters are useful in a number of applications, including:  ### Air  - Monitoring gas flow in plants or labs  - Managing ozone generation for water treatment - Managing the flow of air in food and beverage facilities ### Water - Monitoring the water quality at food and beverage plants  - Monitoring water flow in plants or labs  ### Chemical - Monitoring filtration loading  - Monitoring chemical lines  ### Custom Applications  - Monitoring hydraulic oils with specially calibrated devices  - Monitoring flow in applications that blend materials, such as lines that use a valve meter  ## Variable Area Flow Meter Benefits Variable area flow meters offer many benefits that include:  ### Flexibility Variable area flow meters are useful in a broad area of applications, including hazardous, low pressure, extreme temperatures, low velocity, corrosive, and clean solutions and environments.  ### Reliability As one of the oldest flow measurement devices, the variable area flow meter is known for its reliability across a multitude of materials and settings. The controller sustains a constant flow rate regardless of variations in the process pressure.  ### Robust Design There are many different types of variable area flow meters, and each is designed to match the requirements of the use application. For harsh industrial applications, variable area flow meters are available in various metals and PTFE coating depending on the application.    ### Easy Installation Many variable area flow meters do not require power. The independence from the power supply makes variable area flow meters easy to install and maintain.  ### Trouble-free Operation Variable area flow meters consist of a simple, straightforward design that allows for trouble-free operation.  ### No External Power Required Variable area flow meters do not require power to operate. This means that the devices can be used in locations where power is inaccessible or not desired for safety reasons.  ### Cost-Effective Both the price and function of variable area flow meters contribute to savings in a multitude of industrial applications. Variable area flow meters can be installed with other types of flow measurement technologies to create economical solutions.  Since 2001, Techstar has been a one-stop-shop for quality instrumentation and analytical products.    TechStar also provides onsite field service support and hands-on training to meet your needs. 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