EXPERIMENT
ROTAMETET SET-UP
1. OBJECTIVE: Study
of flow measurements using rotameter – Calibration and discharge measurement
using rotameter.
2. INTRODUCTION: A rotameter is an industrial device that is used
to measure the flow rate of liquids and gases through a tube. Its operation is
based on the variable area principle: fluid flow raises the float in a tapered
tube, increasing the area for the passage of the fluid. In these devices, the falling and rising
action of a float in a tapered tube provides a measure of flow rate. It belongs to a class of meters called variable
area meters. A rotameter does not require an external power as a fuel, it uses
only the inherent properties of the fluid, along with gravity, to measure the
flow rate. Since the area of the flow passage increases as the float moves up
the tube, the scale becomes approximately linear. It works on the principle of
up thrust force exerted by fluid and force of gravity. In the variable area flowmeters,
the drop rate is constant and the flowrate is a function of area of
constriction. It is used in wide range of applications such as the measurement
and control of machinery, control of gas burners flow control of industrial
refrigeration. The density of the liquid should be enough for the plummet to
float or else the reading would be incorrect.
3. PROCEDURE:
1.
Shut down the valves before the experiment.
2.
Switch on the mains, the indicator will start showing a red light then Switch
on the pump.
3.
Fill the sump tank up with liquid for calibration.
4.
Switch on drain valve to the sump tank and measure the amount of liquid lost on
every 1 cm decrease in the level indicator of the measuring scale
(calibration).
5.
Take multiple readings and find the mean volume collected for every 1 cm
decrease in level. This reading is the experimental volume occupied by the
liquid, for theoretical volume calculations, find the volume of the tank by
measuring its dimensions and calculate liquid lost per 1cm decrease in height.
6.
Find % error in theoretical and experimental volume readings
7.
Close all the valves, slightly open the bypass valve and switch the pump on.
Control the flow rate of the liquid by handling the control valve, find the
minimum and maximum flow rate of the liquid. Close the bypass valve for maximum
flow rate. Maintain the rotameter at a constant flow rate and collect the
liquid in the measuring tank for seconds by tilting the flow diverter.
8.
Note the volume of liquid collected by measuring the height on the level
indicator. Repeat this step 3 times for a certain flow rate (in LPH) and take
the concordant reading. Note the different amounts of volume collected at
different LPH, starting from the minimum to the maximum flow rate. Find the %
error in theoretical vs experimental flow rate and plot the graphs
4. OBSERVATION
WIDTH OF MEASURING TANK =
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cm
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LENGTH OF MEASURING TANK =
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cm
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AREA OF MEASURING TANK =
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cm2
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MEASUREMENT
OF
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ROTAMETER =
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LENGTH= cm
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S.NO
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FLOW RATE (LPH)
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H1
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H2
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DIFF.(H2-H1)
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TIME
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Lt/hr
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(cm)
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(cm)
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(cm)
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(sec)
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