Kobold NBK-ATEX Series User manual

Operating Instructions
for
Bypass Level Indicator
Model: NBK-ATEX

NBK-03 to -33 ATEX
page 2 NBK-03 to -33 ATEX K10/0322
1. Contents
1.Contents ........................................................................................................ 2
2.Note .............................................................................................................. 3
3.Instrument Inspection .................................................................................... 4
4.Regulation Use ............................................................................................. 4
4.1Bypass Measuring Tube System ......................................................... 5
4.2Electrical Limit Switches (option) ......................................................... 5
4.3Reed Contact Resistance Chain
(ATEX: options ...2/...E/...R/...B/...4/...L/...K/...N) ................................. 5
5.Operating Principle ........................................................................................ 6
6.Mechanical Connection ................................................................................. 7
7.Electrical Connection .................................................................................... 9
7.1Limit contacts NBK-R, NBK-RT, NBK-RA ............................................ 9
7.2Wiring Diagram .................................................................................. 10
7.3Safety Instructions ............................................................................. 13
7.4Ground connection for ATEX models ................................................ 15
8.Commissioning............................................................................................ 16
9.Trouble Shooting ......................................................................................... 17
10.Maintenance ............................................................................................... 17
11.Technical Information .................................................................................. 18
12.Options ........................................................................................................ 26
13.Order Codes ............................................................................................... 31
14.Dimensions ................................................................................................. 32
15.EC Declaration of Conformance ................................................................. 37
16.Certificates .................................................................................................. 40
16.1NBK-EXAM ........................................................................................ 40
16.2Transmitter LOM ................................................................................ 48
16.3Limit contact RA (excerpt) .................................................................. 53
Manufactured and sold by:
Kobold Messring GmbH
Nordring 22-24
D-65719 Hofheim
Tel.: [phone]
Fax: [phone]
E-Mail: [email protected]
Internet: www.kobold.com

NBK-03 to -33 ATEX
NBK-03 to -33 ATEX K10/0322 page 3
2. Note
Please read these operating instructions before unpacking and setting the unit into
operation. Follow the instructions precisely as described herein.
The instruction manuals on our website www.kobold.com are always for currently
manufactured version of our products. Due to technical changes, the instruction
manuals available online may not always correspond to the product version you
have purchased. If you need an instruction manual that corresponds to the
purchased product version, you can request it from us free of charge by email
([email protected]) in PDF format, specifying the relevant invoice number and
serial number. If you wish, the operating instructions can also be sent to you by
post in paper form against an applicable postage fee.
The devices are only to be used, maintained and serviced by persons familiar with
these operating instructions and in accordance with local regulations applying to
Health & Safety and prevention of accidents.
When used in machines, the measuring unit should be used only when the
machines fulfil the EC-guidelines.
Classification according to Pressure Equipment Directive 2014/68/EU
NBK-03 to NBK-33
Cate
g
or
y
assi
g
nment for dan
g
erous media
(
from dia
g
ram 1
)
Density
[kg/dm³]
PN
[bar
]
Category ML
[mm]
Category ML
[mm]
Category ML
[mm]
NBK-03
1,0
16
← Cat. II →
4711
← Cat. III →
6000 - / -
0,9/0,8/0,7/
0,6/0,54 4600 6000 - / -
NBK-06
1,0
40
1698 6000
← Cat. IV →
∞
0,9/0,8/0,7 1588 6000 ∞
NBK-07
1,0
63
1060 6000 ∞
0,9/0,8/0,7 950 6000 ∞
NBK-10
1,0
100
577 4084 ∞
0,9/0,8 467 3974 ∞
NBK-31
1,0
160
≤2090 5600
0,9 ≤2020 5600
0,8 ≤1900 5400
NBK-32
1,0
250
≤1180 5600
0,9 ≤1110 5600
0,8 ≤985 5400
NBK-33
1,0
320
≤1040 5600
0,9 ≤970 5500
0,8 ≤830 5400
ATTENTION! If the calculated bypass length is exactly within the range limit, then the stricter test method must be used

NBK-03 to -33 ATEX
page 4 NBK-03 to -33 ATEX K10/0322
Classification according to Pressure Equipment Directive 2014/68/EU
NBK-03 to NBK-33
Cate
g
or
y
assi
g
nment for not dan
g
erous media
(
from dia
g
ram 2
)
Density
[k
g
/dm³]
PN
[bar]
Kategorie ML
[mm]
Category ML
[mm]
Category ML
[mm]
Category ML
[mm]
NBK-03
1,0
16
← Cat. I →
4711
← Cat. II →
6000
← Cat. III →
6000 - / -
0,9/0,8/0,7/
0,6/0,54 4600 6000 6000 - / -
NBK-06
1,0
40
1698 6000 6000 - / -
0,9/0,8/0,7 1588 6000 6000 - / -
NBK-07
1,0
63
1060 6000 6000
← Cat. IV →
∞
0,9/0,8/0,7 950 6000 6000 ∞
NBK-10
1,0
100
577 4084 6000 ∞
0,9/0,8 467 3974 6000 ∞
NBK-31
1,0
160
≤2090 5600 - / -
0,9 ≤2020 5600 - / -
0,8 ≤1900 5400 - / -
NBK-32
1,0
250
≤1180 4410 5600
0,9 ≤1110 4340 5600
0,8 ≤985 4220 5400
NBK-33
1,0
320
≤1040 4090 5600
0,9 ≤970 4010 5500
0,8 ≤830 3870 5400
ATTENTION! If the calculated bypass length is exactly within the range limit, then the stricter test method must be used
3. Instrument Inspection
Instruments are inspected before shipping and sent out in perfect condition.
Should damage to a device be visible, we recommend a thorough inspection of the
delivery packaging. In case of damage, please inform your parcel service /
forwarding agent immediately, since they are responsible for damages during
transit.
Scope of delivery:
The standard delivery includes:
 Bypass Level Indicator model: NBK-…
4. Regulation Use
Any use of the Bypass level Indicator, model: NBK, which exceeds the
manufacturer’s specification, may invalidate its warranty. Therefore, any resulting
damage is not the responsibility of the manufacturer. The user assumes all risk for
such usage.
The NBK Bypass Level Indicator is used for continuous measurement, indication,
and monitoring of liquids in tanks, vessels, reservoirs, basins etc. The indication
occurs via a magnetically coupled roller indicator.

NBK-03 to -33 ATEX
NBK-03 to -33 ATEX K10/0322 page 5
4.1 Bypass Measuring Tube System
The bypass tube is attached at the side of the vessel with a connecting flange or a
threaded pipe. The installation position is always vertical. The NBK should only be
used for liquids with the medium density specified on the nameplate. Otherwise the
indication will deviate (float too high or submerged).
Vessel inner pressure and medium temperature should not exceed the specified
maximum values, as this can lead to the destruction and malfunction of the bypass
system. It is imperative that the materials used are compatible with the liquid being
measured.
Proper operation is also impaired by:
 high degree of soiling
 suspended solids
 crystallisation
 ferrite particles
4.2 Electrical Limit Switches (option)
The optional electrical limit switches serve to signal a preset level.
For ATEX: NBK-RA: Bistable changeover contact as encapsulated proximity
switch fitted in metallic cast housing with 3 m connection cable.
4.3 Reed Contact Resistance Chain
(ATEX: options ...2/...E/...R/...B/...4/...L/...K/...N)
The optional reed contact resistance chain (model: MM..., see separate EC-Type
Examination Certificate LOM14ATEX2075X) converts the liquid level to a
resistance value. It serves to electrically transfer the level value. An optional
available transmitter converts the resistance value into a standard signal (e.g. 4-
20 mA).
Please pay attention to the maximum medium and ambient temperatures.

NBK-03 to -33 ATEX
page 6 NBK-03 to -33 ATEX K10/0322
5. Operating Principle
Kobold Bypass Level Indicators are used for continuous measurement, display and
monitoring of liquid levels. The bypass tube is attached onto the side wall of the
vessel.
According to the law of communicating tubes the level in the bypass tube equals
the level in the vessel. A float with embedded circular magnets in the bypass tube
follows the liquid level and transfers it in a non-contacting manner to a display or a
monitoring device fitted outside the tube. The following indication and monitoring
devices are available:
Magnetic roller indicator
As the float passes by, the red/white rollers are rotated in succession by 180°
around their own axes. The rollers change from white to red as the level rises and
from red to white as the level falls. The advantage of ball displays is the higher
protection category, good visibility of 180 ° and higher vibration resistance with
filled version. The level in a tank or a mixer is continuously displayed as a red
column, even when the power supply fails.
Transmitter
To remotely transmit the level a transmitter with an immersible magnetic probe
(chain of resistors) or a magnetostrictive transducer can be mounted outside the
bypass tube. The contacts of a reed contact chain are connected or disconnected
via the float movement in a non-contacting manner. Depending on the level the
number of connected resistors changes and as a consequence the output of the
total resistor value. A continuous standard signal of 4 to 20 mA is generated by
means of a fitted transmitter. This standard signal can then be displayed on
analogue or digital indicating devices.
Limit contacts
One or more reed contacts for limit-value acquisition or also for level control can
be attached to the bypass tube.
ATEX-version only NBK-03...NBK-10
The bypass level indicators are ATEX approved. For level evaluation, limit switches
and a magnetic submersible probe (reed contact chain) with ATEX approval are
offered. The electrical add-on parts have their own ATEX approval.
ATEX approval:
Bypass-level indicator: II 2G Ex mb IIC T5/T6 Gb
Limit contact NBK-RA: II 2D Ex mb IIIC IP67 T 105 °C Db
Reed Contact Resistance Chain: II 1GD Ex ia IIC T6 Ga
II 1/2G Exd II C T6 Ga/Gb
II 1/2D Ex tb IIIC T85 °C Da/Db

NBK-03 to -33 ATEX
NBK-03 to -33 ATEX K10/0322 page 7
6. Mechanical Connection
Remove the bottom flange from the
bypass tube, and insert the
cylindrical float in the NBK bypass
tube with the designation "TOP"
upturned. Reposition the gasket
and close the bottom flange again;
firmly tighten with screws.
Mount the bypass tube to the
vessel to be monitored via the
process connection and seal with
an appropriate device. Normally it
is sufficient to fix the complete NBK
with both process connections.
However the NBK should be
subjected to constant shock or
strong vibrations it is
recommended that the instrument
is secured with rubber-damped
tube clips. No welding is allowed on
the bypass tube.
Mount and tighten the magnetic
roller indicator - if not already
mounted - on the bypass tube with
the two provided ribbon clamps.
Mount and tighten the reed switch - if available - on the bypass tube at the opposite
side of the roller indicator with the provided ribbon clamps (ex contact: two ribbon
clamps). The height of the switch contacts may be selected at will. The cable connec-
tion must point downwards. The switch must be attached close to the bypass tube. The
switching function of the switch is impaired by an enlarged air gap.

NBK-03 to -33 ATEX
page 8 NBK-03 to -33 ATEX K10/0322
Mount and tighten the remote sensor -
if available and not already mounted - on
the bypass tube with the ribbon clamps.
The remote sensor must fully cover both
process connections. The cable terminal
box is situated at the top.

NBK-03 to -33 ATEX
NBK-03 to -33 ATEX K10/0322 page 9
7. Electrical Connection
7.1 Limit contacts NBK-RA
Attention!
Observe the allowed electrical ratings for the limit switch.
Maximum values
NBK-RA
ATEX-
contact
Switching capacity: 45 W/VA
Switchin
g
current: 0,6
A
Switching voltage: 230 VAC/DC
Install the switch (if available) according to the diagram and connect it to the
electrical controller.
When switching inductive loads, such as contactors, relays, etc., electrical limit
values should not, also temporarily, be exceeded by e.g. voltage peaks. The use
of a contact protection relay is recommended to avoid overloading the reed
contacts.
Valid regulations for hazardous areas and regulations for installation (DIN/VDE
0165) should be observed when installing the NBK level indicator in zone 1 or 2
hazardous areas (no combustible liquids).
Note to NBK-RA:
Protect the circuit of the limit contact with a fuse. This fuse
must tolerate the permitted nominal current of the switching
contact and must have a deactivating ability according to the
possible short circuit current of the power system at the place
of installation. The contact is activated by the North Pole of a
magnet and deactivated by its South Pole.
NBK-RA
A
TEX- contact
brown
blue
black

NBK-03 to -33 ATEX
page 10 NBK-03 to -33 ATEX K10/0322
7.2 Wiring Diagram
 Ensure that the electrical supply lines are powerless.
 To avoid faults caused by electrical fields from other circuits, the cables should not
be installed adjacent to other high voltage power lines.
 Unscrew cover and run supply lines through cable gland.
 Connect the remote sensor to the electronics according to the following table.
7.2.1 Reed Contact Chain Resistor Output
(ATEX options ...2/...4)
Resistance value
increases
proportionally
with level
increase.
Resistance value
decreases
proportionally
with level
increase.
Signal
Internal* White Brown Green
Models with box Clamp 1 Clamp 2 Clamp 3
*Please note: The colours of internal cables are for internal connections
only and therefore are only visible in transmitters with terminal
connection box