Orion Instruments Atlas - Manual (Page 15)

46-638 Magnetic Liquid Level Indicators 15
Local indication, 4–20 mA output, HART and Fieldbus
protocols are available. Float damage will not result in loss
of the 4–20 mA signal
Aurora: The Eclipse Guided Wave Radar probe is mount-
ed directly inside of the Gemini chamber. a minimum
3" chamber is utilized to accommodate the Eclipse probe
and allow unobstructed float travel. Patent pending.
Gemini: The dual chamber approach also accomplishes
total redundancy but increases the ease of gauge or trans-
mitter isolation. The Atlas gauge provides local indication
while the Eclipse is mounted directly inside a connected
second chamber. The units perform independently of
each other.
2.2 Theory of Operation
2.2.1 Side Mount
A float equipped with a strong magnet assembly inside and
weighted to the specific gravity of the fluid to be measured,
moves up and down in a non-magnetic chamber, as the
fluid inside rises and falls with the level of the liquid in
the vessel.
Attached to the external wall of the non-magnetic chamber
is a non-porous glass tube. Inside this hermetically sealed
glass tube is a highly visible fluorescent orange indicator or
flags with a strong magnetic assembly inside. See Figures
12 and 13.
The indicator is always coupled to the float magnetically,
to indicate the exact measurement of the fluid.
2.2.2 Top Mount
A top mounted float assembly consisting of a magnet
assembly at the top, a guide rod in the middle, and a float
at the bottom. The float at the bottom is submerged in the
liquid inside the vessel. The entire guide rod assembly is
weighted to the specific gravity of the fluid to be measured.
Attached to the external wall of the non-magnetic chamber
is a non-porous glass tube. Inside this hermetically sealed
glass tube is a highly visible fluorescent orange indicator or
flags with a strong magnetic assembly inside. See Figures
12 and 13.
The indicator or flags are always coupled to the magnetic
assembly, to indicate the exact measurement of the fluid.
Stainless steel
chamber wall
Float
magnets
Liquid
level
Float
Flux ring
Indicating
flags
Flux
ring Magnet
spacer
Figure 13
Figure 12