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Magnetic Level Gauge
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 Left
drawing shows a typical BONT® Magnetic Level Gauge, used in level
control of any kind of fluid.
The Magnetic Level Gauge is the instrument to read a level indication
in whatever plant or operating conditions giving free maintenance,
preventive security against leakage, environmental safety, sure
and trouble free application with chemically aggressive, pollutant, harmful
or poisonous, inflammable or explosive, optically similar fluid interface.
Our very wide range of Magnetic Level Gauges allows to have the proper instrument for any kind of plant or specific purpose. Our world patented system includes a float able to float both in high density fluid or in low density fluid up to 0.4 specific gravity. But more! You can have low specific gravity and high temperature and pressure together (i.e. water/steam of H.P. vessels). Well! We manufacture a float able to float and to resist with external pressure of 210 bar at 370 ºC!.And more! Do you need Remote Direct Reading? We have it, as a completion of Magnetic or Glass level Gauge. Are you looking for a Transmitted Remote Signal? We can supply a sensing element able to transduce the signal to LED, Analog or Recording Instruments that you can have in the Control Room. |
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DESIGN
In
a vertical chamber (tube of suitable diameter connected by
stub ends to the vessel) there is a float containing a permanent
magnet -fixed by means of special patented device that permit
to the magnet a 360º rotation- placed exactly on liquid level line.
Magnetic action of permanent magnet in the float generates rotation
of a set of small permanent magnets enclosed in small cylinders-contained
in indicating scale-which cylinders, having different colors in
the North and South pole, can rotate on their horizontal axis.
So the
scale appears of one color (i.e. white) over chamber area taken
by gas and of another color (i.e. red) over chamber area taken
up by liquid phase.
The chambers of the Magnetic Level Gauge are dimensioned according
to ASME B31.1 and B31.3.
The chamber is connected to vessel with flanged, threaded or
welded ends. Usually, between the instrument and its connecting
ends valves are fitted to consent shut-off piping and to disassemble
the level gauge without empting the vessel or shutting off the plant.
Drain valves can also be fitted on the top and bottom of level gauge.
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MAGNETIC
LEVEL GAUGE OPERATING PRINCIPLE
Operation
of BONT Magnetic Level Gauge is based on some elementary physical
principles:
- The
principle whereby liquid in communicating vessels is always
at same level;
- Archimede's
principle according to which a body immersed in a liquid
receives a buoyancy equal to the weight of displaced liquid;
- The
principle of attraction between North and South poles of
two permanent magnets and that of repulsion between like poles.
- This
principle has two applications in the BONT magnetic level
gauge:
- first
between the magnet in the chamber float and every single
magnet of the indicating scale:
- second
between the magnets of the indicating scale.
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 The
cylindrical magnet "A" in the float is able to turn
horizontally on the axis "B" like a compass needle, so that
magnetic force is always free to best orientate itself towards the
magnetic scale, in which small cylinders "C", rotating vertically
on their axis "D", contain smaller cylindrical magnets
fitted in orthogonal position to rotation axis.
Cylinders No. 1 & 2 are in stable position, as cylinders
4 & 5, because the magnetic chain between their magnets
is well oriented "N-S-N-S"; cylinder No. 3 is in not
stable position because North Pole "N" of the bigger
magnet "A" inside the float attracts the South Pole "S"
of the smaller magnet inside the cylinder. The same cylinder
tries to rotate clockwise because its "N" pole would
reach the "S" pole of cylinder 2. Imagine now that
fluid, growing in the level gauge, pushes up the float. The
float magnet, going upside, will approach the cylinder 4, attracting
its "S" pole, and so, after clockwise rotation, it
will be in the same position as now the cylinder 3. Same cylinder
3 will be in that case free to complete rotation clockwise,
and its position will became stable as cylinder 1 & 2. And
so and so with growing of the liquid level. The same, with inverse
rotation of small cylinders, happen when the float goes down. |
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Remote
Direct Reading (RDR) Magnetic Gauge
With
the use of electronic sensers remote direct reading from afar is
easily achieved with the RDR Magnetic Gauge. The system may be connected
to a cherry system, LED connector or a Transducer with an Analog
converter for connection to a digital device or indicator. The system
can be installed on any boiler or tank. Only two connections is
sufficient for installation.
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