Rotameter

Rotameter outline

Rotameter

A rotameter is a device that measures the flow rate of liquid or gas in a closed tube. It belongs to a class of meters called variable area flow meters, which measure flow rate by allowing the cross-sectional area the fluid travels through to vary, causing a measurable change.

Design and Operation

The rotameter consists of a tapered tube, typically made of glass, with a float inside that is pushed up by the flow of the fluid and pulled down by gravity. The position of the float is an indication of the flow rate. The tube is wider at the top than at the bottom, which means that as the float rises, the area between the float and the tube wall increases, allowing more fluid to pass around the float.

The float reaches a stable position when the upward force exerted by the fluid flow equals the downward gravitational force on the float. The height of the float is then read off a scale on the tube, which is calibrated to the flow rate.

Applications

Rotameters are widely used in various industries, including chemical, pharmaceutical, and water treatment industries. They are used for applications such as monitoring the flow of gases in laboratory experiments, controlling the flow of liquids in industrial processes, and measuring the flow rate of water in water treatment plants.

Advantages and Disadvantages

Advantages

• Simple and reliable design
• No external power required
• Can be used for both liquids and gases
• Provides a visual indication of flow rate

Disadvantages

• Limited to low-pressure systems
• Glass tubes can be fragile
• Accuracy can be affected by changes in fluid density and viscosity

Related Pages

• Flow measurement
• Variable area flow meter
• Fluid dynamics
• Industrial process
• Water treatment

See Also

• Flow meter
• Turbine flow meter
• Ultrasonic flow meter
• Coriolis flow meter