A rotameter (variable area meter) is a flow meter that measures volumetric flow of liquids and gases. ... 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.

How does a rotameter flow meter work?

A Rotameter is a form of variable area flow meter which has a simplistic operation whereby a liquid or gas passes through a tapered tube. In order for this gas to pass through the tube it must first raise a float held within the tube. ... In both cases, the greater the flow then the higher up the tube the float moves.

What is rotameter used for?

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

How do you measure rotameter flow?

The metering tube in a rotameter is installed vertically (Figure 2-15) and the small end is at the bottom. The fluid that is going to be measured enters at the bottom of the tube, passes upward around the float, and exits the top. If there is no flow, then the float stays at the bottom.

Under what conditions is the rotameter used?

Typically they can be used for corrosive liquids that attack glass tubes, in cases where water hammer due to flows that suddenly start or stop is important, or under higher temperatures or pressures such as those associated with steam, which can destroy glass rotameters.

Rotameter (Working And Animation)

43 related questions found

What is the difference between rotameter and flow meter?

A rotameter (variable area meter) is a flow meter that measures volumetric flow of liquids and gases. There is no difference between a rotameter and flow meter, and these terms are used interchangeably. ... The flow rate is then read from either a scale next to the tube or a scale on the tube.

How do you measure a flow meter accuracy?

If the absolute accuracy is +/- 10 kg/h - the relative accuracy at full scale 1000 kg/h can be calculated as:

1. a_% = (+/- 10 kg/h) 100% / (1000 kg/h) = +/- 1%
2. a_% = (+/- 10 kg/h) 100% / (100 kg/h) = +/- 10%
3. a = (+/- 1%) (1000 kg/h) = +/- 10 kg/h.
4. a = (+/- 1%) (100 kg/h) = +/- 1 kg/h.

How does a flow meter work?

A flow meter works by measuring the amount of a liquid, gas, or steam flowing through or around the flow meter sensors. ... Flow meters measure either volume or mass. The flow (Q) is equal to the cross-sectional area of the pipe (A) in a volumetric flow meter, and the velocity of the flowing fluid (v): Q = A * v.

How do you read a flow meter?

The gas flow rate is read from the position of the top of the bobbin of the flow meter. In flow meters with a ball, rather than a bobbin (right), the reading is taken from the centre of the ball.

What is area flow meter?

The variable area flow meter is an industrial flow meter used to measure the flowrate of liquids and gases. ... The variable area meter consists of a tube and float. The float response to flowrate changes is linear, and a 10-to-1 flow range or turndown is standard.

What is Venturi flow meter?

Venturi meters are flow measurement instruments which use a converging section of pipe to give an increase in the flow velocity and a corresponding pressure drop from which the flowrate can be deduced. They have been in common use for many years, especially in the water supply industry.

How many types of flow meter are there?

There are two categories of flow meters: gas and fluid or liquid. Fluid flow meters have five subcategories: differential pressure, velocity, positive displacement, mass flow, and open channel.

What is the difference between rotameter and orifice meter?

The orifice meter, Venturi tube and flow nozzle work on the principle of constant area variable pressure drop. ... On the other hand Rotameter works as a constant pressure drop variable area meter. Rotameter can be only be used in a vertical pipeline.

Are Rotameters accurate?

Even in the most demanding applications — measuring gases, liquids or steam — rotameters can deliver 2% full-scale accuracy. Rotameters are inexpensive flow-metering devices for a variety of industrial processing applications.

What is the principle behind Venturimeter?

The venturimeter works on the principle of Bernoulli's equation, i.e., the pressure decreases as the velocity increases.

How is flow measured?

Flow is the volume of fluid that passes in a unit of time. In water resources, flow is often measured in units of cubic feet per second (cfs), cubic meters per second (cms), gallons per minute (gpm), or other various units.

How do you read flow rate on rotameter?

Connecting the rotameter with the fluid flowing source, to initiate the process. The float starts to swim in the middle of the tapered pipe due to the velocity of the fluid. The side of the meter has a scale. The lower and upper level of the float is to be measured by that scale, which gives the flow rate.

Where is the flow meter located pool?

Flow meters used in swimming pools are typically installed directly in the plumbing on a long, straight section of pipe.

What is the maximum range of flow rate measurement?

Flow ranges of up to 100:1 are available. Insertion style meters are typically in the range of $400 to $1000.

What is full scale accuracy?

Full scale accuracy means that wherever you are reading within the scale, the error is the same. For example, a 1000 psi pressure gauge with an accuracy of ±1 % of scale (ASME B40.

What is the maximum full range of differential flow meters?

The turndown of the meter can be extended to around 10:1 if multiple range transducers are used. For example, one Δp transducer could be ranged for 1 – 10% FS and another over the range of 10 – 100% FS.