Kobold NM Specifications

NM
LIQUID LEVEL TRANSDUCER

Flow
Pressure
Level
Temperature

measurement
monitoring
control

Model:

NM

Visit KOBOLD Online at

www.kobold.com

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

☎

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

USA

CANADA

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

☎

[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

Subject to change without prior notice. Rev 4/12

N2

NM - Liquid Level Transducer

The NM-298 and NM-299 are stainless
steel level transducers which are
installed upwards into a threaded fitting.
This arrangement requires access to the
interior of the vessel into which the units
are installed.

Each transducer comes standard with

3.3 feet (1 meter) of pigtail cable. Extra
cable lengths are available.

The NM-298 is ideal for installations 6.6
feet (2 meters) and shorter. The NM-299
can be obtained in lengths to 19.8 feet
(6 meters).

Specifications

Maximum Length

NM-298: 6.6 feet
NM-299: 19.8 feet

Fittings

NM-298:

3

/8" NPT male

NM-299:

1

/2" NPT male

Wetted Parts: 316-Ti SS
Accuracy: ± 15 mm (0.6 in.)
Minimum Liquid Specific Gravity

Standard: 0.8
Optional: 0.7

Temperature Range:– 4 to 250 °F
Max. Pressure

NM-298: 210 PSIG
NM-299: 290 PSIG

Electrical Data

Sensing Voltage: 20 VDC max.
Sensing Current: 100mA max.

Total Resistance

Standard: Approx. 5,000 Ω

Cable Length: 3.3 feet standard

(longer available)

Protection: NEMA 4X/IP65

NM-298 NM-299

Models NM-298 and NM-299: Stainless Steel

Model Number

Series Number Fittings Length

NM-298 -N

3

/8":3/8" NPT -L =: Specify Length

-R 3/8":3/8" bsp

NM-299 -N

1

/2":1/2" NPT

-R 1/2":1/2" bsp

NM-298 and NM-299 Ordering Information

Example: NM-298-N 3/8"-L 40"

NM - Liquid Level Transducer

Rev 4/12 Subject to change without prior notice.

The NM-301 and NM-302 are stainless
steel level transducers with flanged or
threaded fittings. Use of the 1

1

/2" NPT
fitting or flange allows the units to be
installed from the top of your vessel or
mounting bracket. These larger fittings
will accommodate the floats with which
the transducers are equipped. Each
transducer comes standard with a
NEMA 4 terminal box.

The NM-302 is intended for installations

6.6 feet (2 meters) and shorter. The
NM-301 can be obtained in lengths to

19.8 feet (6 meters.)

Specifications

Minimum Length: 12 inches
Maximum Length

NM-301: 19.8 feet
NM-302: 6.6 feet

Fittings

NM 301:

1

/2" NPT male

4" ANSI flange

NM-302: 1

1

/2" NPT male,

2", 2

1

/2" 3" or 4"

ANSI flange

Wetted Parts: 316-Ti SS
Accuracy

NM-302: ± 10 mm (0.6 in.)
NM-301

L< 6.6 feet: ± 10 mm (0.4 in.)
L> 6.6 feet: ± 20 mm (0.8 in.)

Minimum Liquid Specific Gravity

Standard: 0.8
Optional: 0.7

Temperature Range: – 4 to 250 °F
Max. Pressure

NPT Threads

NM-301: 290 PSIG
NM-302: 210 PSIG

Electrical Data

Sensing Voltage: 20 VDC max.

Sensing Current: 100 mA max
Total Resistance

Standard: Approx. 5,000 Ω

Terminal Box: Polyamide
Protection: NEMA 4X/IP65

Optional Transmitter: 2-wire, 4-20 mA,

16-32 VDC input power

NM-301 NM-302

Models NM-301 and NM-302: Stainless Steel

Model Number

Series Number Fittings Length

NM-301 -N

1

/2":1/2" NPT -L =: Specify Length

-FL 4": 4" 150 lb ANSI flange

NM-302 -N 1

1

/2": 11/2" NPT

-FL 2": 2" 150 lb ANSI flange

-FL 2

1

/2": 21/2" 150 lb ANSI flange

-FL 3": 3" 150 lb ANSI flange

-FL 4": 4" 150 lb ANSI flange

Options

-RT Integral 2-wire 4-20 mA Transmitter

NM-301 and NM-302 Ordering Information

Example: NM-302-FL 3", L = 128"

Subject to change without prior notice. Rev 4/12

N2

NM - Liquid Level Transducer

The NM-300 and NM-308 are PVC,
polypropylene (PP) or PTFE
level transducers with flanged or threaded
fittings. PVC floats and flanges are
unavailable. Polyethylene (PE) floats and
polypropylene (PP) flanges will be provided
with PVC units. PVC threaded fittings are
available.

Each transducer comes with a NEMA 4
terminal box.

Specifications

Maximum Length

NM-300: 3.3 feet
NM-308: 19.8 feet

Fittings

NM-300: 2 NPT male

2

1

/2ANSI flange

NM-308: 1" NPT male

3" ANSI flange

Wetted Parts

NM-300:

Stem: PVC or

Polypropylene (PP)

Float: Polyethylene with

PVC stem or PP
with PP stem

NPT Fittings: PVC or PP
Flanged: PP only

NM-308:

Stem: PVC, PP or PTFE
Float: Polyethylene with

PVC stem, PP or
PTFE

NPT Fittings: PVC, PP or PTFE
Flanged: PP or PTFE

Accuracy

NM-300: ± 10 mm (0.4 in.)
NM-308

Below 6.6 feet: ± 10 mm (0.4 in.)
Above 6.6 feet: ± 20 mm (0.8 in.)

Minimum Liquid Specific Gravity

NM-300: 0.5
NM-308: 0.8

Operating Temperature Range

PVC/PE: – 4 to 140 °F
Polypropylene: – 4 to 190 °F
PTFE: – 4 to 250 °F

Max. Pressure: 85 PSIG

NM-300 NM-308

Models NM-300 and NM-308: Synthetic

Model Number

Series Number

Fittings

Length

Tube & Float

(PVC Units w. PP Flange) Material

NM-300 -N 2": 2 NPT -L =: -PVC: PVC (Poly-

(PVC or PP) -FL 21/2": 21/2" 150 lb ANSI flange Specify ethylene float)

Length

-PP: Polypropylene

NM-308 -N 1

1

/2": 11/2" NPT

(PVC, PP or PTFE) -FL 2": 2" 150 lb ANSI flange -PTFE : PTFE

-FL 2

1

/2": 21/2" 150 lb ANSI flange (NM-308 only)

-FL 3": 3" 150 lb ANSI flange

-FL 4": 4" 150 lb ANSI flange

Options

-RT Integral 2-wire 4-20 mA Transmitter

NM-300 and NM-308 Ordering Information

Example: NM-300-FL 21/2"PVC, L=23”

Electrical Data

Sensing Voltage: 24 VDC max.
Total Resistance

Standard: Approx. 5,000 Ω

Terminal Box: Polyamide
Protection: NEMA 4X/IP65
Optional Transmitter: 2-wire, 4-20 mA,

16-32 VDC