Continuous level measuring system
NB 4000
Technical information / Instruction manual
page G
Introduction
The Nivobob
®
NB 4000 is an electromechanic level measuring
instrument for continuous measuring of level or volumes in silos,
hoppers or tanks.
Applications
• Powder, granulate, small or coarse bulk goods
Available for industries such as
• Food
• Grain
• Cement
• Plastics
• others
Features
Process
• Suitable for most types of bulk goods
• Independent of bulk material properties, such as:
Dielectricity and conductivity of the bulk good
Dusty atmosphere in the silo
Changing humidity inside the product
Products that tend to stick
• No mechanical load on the silo roof, the sensor weight
just touches the surface of the material
• Accurate measurement
Service
• Simple installation and commissioning
• Measurement principle easy to understand
• Rope, tape with increased service life
• Low maintenance
Approvals
• Approval for use in Hazardous Locations
ATEX II 1/2 D (zone 20/21) and FM Class. II, III Div.1 Gr. E-G
Mechanic
• Measurement range up to 30m (100ft)
• 1 1/2" process connection possible
• Aiming flange to be mounted directly on a flat silo roof
• Internal tape cleaner for difficult materials
• Robust cast housing, ingress protection IP66
Electronics
• Micro processor controlled measurement
• Diagnostics possibilities
• Output 4-20mA
• Two programmable Relais (can be used as Counting pulse
output or as Failure / Upper stop position)
• Measurement start with external signal or integrated timer
Function
The Nivobob
®
NB 4000 is mounted on the top of the silo. A
sensor weight is driven down into the silo. It is mounted at the
end of a rope or tape which is wound on a motor driven roller.
Upon contact with bulk material, the motor changes the winding
direction and the sensor weight is driven back to the upper stop
position.
During downwards movement of the sensor weight the distance
is electronically measured by the rotations of the internal rope /
tape roller. The microcontroller converts the measured distance
into an output signal, which is a volumetric signal based on the
silo geometry. The output signal is updated, when the sensor
weight touches the bulk material.
Diagnostics
Comprehensive diagnostics possibilities are present:
• Measurement control is done by comparing the moved
distance between up and downward movement and checking
for discrepancy. In case of discrepancy, the sensor weight is
pulled to the upper stop position to ensure, that the sensor
weight is not inside the silo.
• Service interval after a certain amount of measurements and
run time.
• Internal control of motor and motor driver electronic.
Diagnostics is in accordance with NAMUR recommendation
NE107.
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®
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NB 4000
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