Kobold NM Specifications

NM
LIQUID LEVEL TRANSDUCER

Flow
Pressure
Level
Temperature

measurement
monitoring
control

Model:

NM

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KOBOLD Instruments Inc.
1801 Parkway View Drive
USA-Pittsburgh, PA 15205

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[phone]
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E-mail: [e-mail]

USA

CANADA

KOBOLD Instruments Canada Inc.
9A Aviation
Pointe-Claire, QC H9 R 4Z2

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[phone]
Fax [phone]
E-mail: [e-mail]

N2

Rev 4/12

● Continuous Level Measurement

● Undisturbed by Foam

● Vapor Insensitive

● Liquid Interface Detection

● Range of Wetted Parts

NM - Liquid Level Transducer

Rev 4/12 Subject to change without prior notice.

The NM series of level transducers is
applicable to a wide variety of industrial
level indicating applications. A reed chain
and travelling float design allow the
system to function independently of
liquid electrical properties, temperature,
pressure, foaming or the presence of
vapors. With proper float weighting, the
system can be constructed to detect the
interface level of two liquids with
dissimilar specific gravities. A selection
of materials ranging from stainless steel,
to plastic, to PTFE, provide
compatibility with a large variety of
process liquids.

Typical NM applications include waste
water and sewage treatment plants,
charging and mixing bins, containers for
chemicals, beverages or vegetable oils,
remote level indication for rivers or
reservoirs. High reliability is assured by
keeping the moving part count down to a
single, non-friction component (the float.)

Function

The transducer consists of a guide tube
onto which a float is inserted. A magnet
inside the float actuates a series of reed
switches inside the tube. One contact of
the reed switches is connected to a
resistance chain every fraction of an
inch, and the other contact to a common
terminal. The entire system functions as
a three-tap potentiometer whose
resistance is determined by the location
of the float on the guide tube. An optional
electronic signal converter module
(suffix code:"RT") uses this variable
resistance as part of a Wheatstone Bridge
circuit and converts the resistance to an
4-20 mA, 2-wire analog signal for use with
an external display or PLC input.
This module can be specified for any unit
with an integral junction box.
.
.

The accuracy of the system is a function
of the reed switch spacing. This spacing
varies from 10 mm (0.4 inches) to 20 mm
(0.8 inches) depending on transducer
model and overall length. The magnet
closes either one or two switches at all
times. Interpolation allows accuracies of

1

/2the switch spacing.

NM Series Level Gauge