Why rotameter is called area meter

The technique for measuring flow is accomplished by a freely moving float finding equilibrium in a tapered tube. The flow rate is then read from either a scale next to the tube or a scale on the tube. The rotameter is estimated to be in its second century of serving customers and their many and various flow flow meter applications.

Rotameter applications extend across industries because it was and still is an economical way of measuring very low to high flow rates. Customers have been asked why they select rotameters.

Their top six responses are clues as to why a rotameter continues to be successful even after a hundred years. Jim Dillon Global Product Manager. Jim is the global product manager for variable area products rotameters at Brooks Instrument. They are particularly well suited for steam applications, where glass tubes are unacceptable. Plastic Tube variable area flow meter Plastic tubes are also used in some variable area flow meter designs due to their lower cost and high impact strength.

They are typically constructed of polycarbonate, with either metal or plastic end fittings. With plastic end fittings, care must be taken in installation, not to distort the threads. Meters with all plastic construction are available for applications where metal wetted parts cannot be tolerated, such as with deionized water or corrosives.

Such instrumentation packages are used as self-contained purge flow meters. These are among the least expensive and most widely used flow meters.

Their main application is to control small gas or liquid purge streams. They are used to protect instruments from contacting hot and corrosive fluids, to protect pressure taps from plugging, to protect the cleanliness of optical devices, and to protect electrical devices from igniting upon contact with combustibles.

Purge meters are quite useful in adding nitrogen gas to the vapor spaces of tanks and other equipment. Purging with nitrogen gas reduces the possibility of developing a flammable mixture because it displaces flammable gases.

The purge-flow regulator is reliable, intrinsically safe, and inexpensive. As shown in the figure, purge meters can operate in the constant flow mode, where P2 - P0 is held constant at about 60 to 80 in H2O differential.

In bubbler and purge applications, the inlet pressure P1 is held constant and the outlet pressure P0 is variable. The figure describes a configuration where the outlet pressure P0 is held constant and the inlet pressure P1 is variable. They can handle extremely small flow rates from 0.

The most common size is a glass tube variable area flow meter with -in 6 mm connections, a range of 0. The Venturi Effect Introduction to Venturi meters and tubes. How does rotameter measure flow? Where is rotameter used?

How accurate are rotameters? Accuracy of a rotameter. How do flow meters work? What is LPM in rotameter? How do you measure liquid flow? What is the principle of a Venturi meter? What is the principle of rotameter? How do you read a floating flow meter? Why is a rotameter tapered? What is rotameter calibration?

What is head type flow meter? What is Lph in rotameter? How do I choose a flow meter? Top Tips for flowmeter selection. Do you even need a flowmeter? What is meant by Venturi meter? What is mano meter? The float is often stabilized by helical grooves incised into it, which introduce rotation - hence the name.

Other shapes of the floats - including spheres in the smaller instruments may be employed. The pressure drop across the float is equal to its weight divided by its maximum cross-sectional area in the horizontal plane. The area for flow is the annulus formed between the float and the wall of the tube. Both in the orifice-type meter and in the rotameter the pressure drop arises from the conversion of pressure energy to kinetic energy recall Bernoulli's equation and from frictional losses which are accounted for in the coefficient of discharge.