What are the Advantages and Disadvantages of Rotameter?

What are the Advantages and Disadvantages of Rotameter?

Rotameter is a device used to measure the volume of fluids in a closed tube. Rotameters are also called variable area flow meters. These meters determine the flow rate by converting the cross-sectional area when the fluid passes through that area. They then create a measurable result.

Rotameter has a tapering pipe made of glass and afloat. The float is made of different forms. The spheres and ellipsoids are among the most common states of the rotameter. It is not a must for the float to float on the fluid. It should have a greater density than the liquid.


The Working Principle of Rotameters


Rotameter is a moveable area meter. It operates on the principle of upthrust force applied by the fluid and the force of gravity. The fluids reach the tapered line. Some liquids collide with the float. If the liquid is higher, the float also rises. The level of the float is directly related to the liquid flow rate. It also moves up and down to the liquid's flow rate. And the area surrounding the float.


Characteristics of Rotameter


Rotameter has increased to the same scale. These meters have flow rates that are related to the area. What shows that the rotameter is not linear is about 5%.




The loss of pressure over the float is an essential feature of the rotameter. The overall differential through the meter increases at high flow rates because of friction in the fittings.




Most Rotameters have high accuracy levels. They are usually plus or minus two of full-scale reading. The accuracy increases if you calibrate it or the length of the scale. The repeatability of these meters is generally excellent.




Rotameters are among the most common flow meters in the flow measurement industry. The more enormous capacities vary from 0.5cm, and the standard is 30 cm.


Minimum Piping Needs


You can install these meters without considering connections. Also, most people do not consider the lengths of straight pipe processes when installing this meter.


Corrosive Fluids


Rotameters can measure corrosive fluids well. They often measure liquids like;

· Oils

· Tar

· Coolants

· Sulfuric acids

· Black liquor

· Beverages

· Aqua regia

· And molten sulfur


Pressure Drops


The rotameter can manage the low-pressure loss. You can do this by putting very light floats on big gauges.


Parts of A Rotameter


Rotameters are made in a mandrel and annealed to prevent inner stresses from getting that strong pipes. The method also allows the creation of lines with enormous productivity.




Floats are made from several materials. This is to get resistance to corrosion. The arrangement is usually in terms of the capacity of the meter. Also, the float's shape helps to determine how the rotameter will be affected by the changes in the thickness of the liquid. Floats that have sharp edges are usually not affected by the change in viscosity.


Advantages of Rotameter


· The cost for rotameter is low

· They have low-pressure drops

· Their range is the best

· These meters are perfect for small flow rates

· They are equipped with alarms and switches.

· They are also excellent in measuring the flow of corrosive fluids.

· You can as well find thickness immune floats

· You can use these meters to measure slurry fluids




· Glass tubes or pipes are hard to handle when determining the flow of fluids

· You have to mount it in a vertical way to measure the flow properly

· It is not fit for pulsating applications

· They measure fluids in small pipes

· They are usually fit for low temperatures

· Their accuracy levels are lower compared to other meters

· They require straight lines to measure the flow of liquids


Applications of Rotameter


Rotameters monitor the extraction of off-show platforms. They are durable and straightforward, which makes them best for controlling the injection of substances in the fluids to prevent corrosion. They also are used to transmit coolants, dry gas, and lubricants.

They are also used in industrial process analyzers. Installing these meters helps you to see early signs of clogging in the flow. The clogging may affect the flow rate of liquids. When choosing a rotameter, always make sure you use it for the right application. If you fail to do it, the accuracy levels may be affected.

Also, make sure you know the size of the tube before you install your meter. Rotameters have ranging sizes, so it is essential to speak to the manufacturer to give fittings. Many rotameter creations are available in the market. Always choose the one that is perfect for your application.




Rotameters are cheap and best for measuring the flow rate of liquids. These meters are used in many applications and are still economical. You can use them to measure flow from low to high flow rates. Always choose a meter that will serve you for a long time. Also, seek help from the seller to help you select the best design.

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