Rotameters, also referred to as variable area flow meters, have diverse industrial processing applications that range from simple to sophisticated. The devices are easy to install, require no electrical connection, and provide direct flow rate reading. They provide fail-safe flow rate readings in a wide array of industrial applications.Rotameters: An Overview
Developed by German inventor Karl Kueppers in 1908, Rotameters measure the volumetric flow rate of liquids and gases.
Important elements of a rotameter (variable area flow meter) include the tube and the float. Their operation is simple. The tube is fixed vertically and the fluid is fed from the bottom. It travels upward and exits from the top. The float remains at the bottom when no liquid is present and rises upward when fluid enters the tube.
The float inside the tube moves in proportion to the rate of fluid flow and the area between the tube wall and the float. When the float moves upward, the area increases while the differential pressure decreases. A stable position is reached when the upward force exerted by the fluid is equal to the weight of the float. A scale mounted on the tube records the flow rate of the liquid. Usually, the flow can be adjusted manually using a built-in valve.
Types of Rotameter
Variable area flow meters can be categorized by the type of tube they use, which relates to their ability to withstands various pressures, temperatures, process media, and cost. Process connection size and wetted part materials vary as a function the rotameter type and construction.
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| Glass Tube Rotameter (Yokogawa) |
Applications:
- Analytical instrumentation
- Industrial processes
- Chemical production
- Pharmaceutical production
- Oil & gas extraction
- Refining processes
- Fuel cell research
- Water treatment systems
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| Metal Tube Rotameter (Yokogawa) |
Applications:
- Purge liquid/ gas metering
- Liquid, oil, or gas flow measurement
- Chemical injection
- Rotating equipment flow measurement
- High-pressure flow meters on offshore oil platforms
