Kobold NBK-M Operating Manual
Operating Instruction
for
Mini Bypass Level
Indicator
Model: NBK-M
NBK-M
1. Contents
1. Contents ........................................................................................................ 2
2. Note .............................................................................................................. 3
3. Instrument Inspection .................................................................................... 3
4. Regulation Use .............................................................................................. 4
4.1. Bypass measuring tube system ........................................................... 4
4.2. Electrical limit switches (option) ........................................................... 4
4.3. Remote Sensor Reed Contact Chain of Resistors (option ..M.. / option
4.4. Remote sensor magnetostrictive sensor (option ..T..) ......................... 5
5. Operating Principles ...................................................................................... 5
6. Mechanical Connection ................................................................................. 6
7. Electrical Connection .................................................................................... 7
7.1. Switch (option) ..................................................................................... 7
7.2. Remote sensor Reed Contact Chain of Resistors (option ..W..) .......... 7
7.3. Remote Sensor: Chain of Resistors with 2-wire Transmitter (option
7.4. Remote Sensor: Magnetostrictive Sensor with 4-wire Transmitter
8. Commissioning .............................................................................................. 9
9. Trouble Shooting ......................................................................................... 10
10.Maintenance ............................................................................................... 10
11.Technical Information .................................................................................. 11
12.Order Codes ............................................................................................... 12
13.Dimensions ................................................................................................. 13
14.Options ........................................................................................................ 15
15.EU Declaration of Conformance .................................................................. 16
Manufactured and sold by:
..W..) .................................................................................................... 5
..M..) .................................................................................................... 8
(option ..T..) ......................................................................................... 8
Kobold Messring GmbH
Nordring 22-24
D-65719 Hofheim
Tel.: +49(0)6192-2990
Fax: +49(0)6192-23398
E-Mail: info.de@kobold.com
Internet: www.kobold.com
Page 2 NBK-M K03/0717
NBK-M
2. Note
Please read these operating instructions before unpacking and putting the unit
into operation. Follow the instructions precisely as described herein.
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 EWG-guidelines.
Classification per PED 2014/68/EU
In acc. with Article 4, Paragraph 3, "Sound Engineering Practice", of the
PED 2014/68/EU no CE mark.
Diagram 1, Pipe, Group 1 dangerous fluids
Diagram 2, Pipe, Group 2 no dangerous fluids
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:
Mini Bypass Level Indicator model: NBK-M
Operating Instructions
NBK-M K03/0717 Page 3
NBK-M
4. Regulation Use
Any use of the Mini-Bypass Level Indicator, model: NBK-M, which exceeds the
manufacturer’s specifications, 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-M Mini Bypass Level Indicator is used for continuous measurement,
indication, and monitoring of liquids in tanks, vessels, reservoirs, basins etc.
Information is displayed on a magnetically coupled roller indicator.
4.1. Bypass measuring tube system
The bypass tube is attached at the side of the vessel with a connecting flange or
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 and the float may sink or float too high.
Vessel inner pressure and medium temperature should not exceed the specified
maximum values, as this can lead to the destruction and/or malfunction of the bypass system. It is imperative that the materials used are compatible with to the
liquid being measured.
Proper operation is also impaired by:
High degree of soiling
Large suspended particles
Crystallisation
Ferrite particles
4.2. Electrical limit switches (option)
The optional electrical limit value controllers serve to signal a preset level.
Important!
Attention !
Observe the approved electrical ratings for the limit value controller.
Maximum values
Breaking capacity: 60 VA 80 VA
Switching current: 0.8 A 1 A
Switching voltage: 230 V 230 V
Page 4 NBK-M K03/0717
Standard
contact
High temperature
contact
NBK-M
4.3. Remote Sensor Reed Contact Chain of Resistors
(option ..M.. / option ..W..)
The optional remote electrical sensor converts the liquid level to a resistance
value, which serves to transmit the level as an electrical signal. Downstream
control electronics transform the signal to a standard signal (e.g.
4–20 mA), or control the level.
Please note max. medium and ambient temperatures.
4.4. Remote sensor magnetostrictive sensor
(option ..T..)
Remote level transmission can be achieved by mounting a magnetostrictive sensor outside the bypass tube. A continuous standard 4 to 20 mA signal is obtained
with a built-in transmitter. This signal can then be displayed on analogue or digital
indicators.
Please pay attention to the maximum medium- and the ambient
temperatures!
5. Operating Principles
The NBK-M works according to the principle of communicating tubes with a float,
that is, the level in the bypass tube corresponds to the level in the vessel. A float
with encased ring magnet in the bypass tube follows the liquid level, and transfers
it, in a non-contacting manner, to a roller indicator that is externally attached. As
the float passes by, the red/white rollers rotate through 180° about their own axis.
Red indicates the actual level, whereas white means no level.
Contact devices and / or remote sensors can also be fitted. The arrangement is
not important as the annular magnetic field acts in all directions.
NBK-M K03/0717 Page 5
NBK-M
6. Mechanical Connection
Standpipe
Indicator
Float
Roller
indicator
Remove bottom flange from bypass
tube, and insert the cylindrical float in
the NBK bypass tube with the designation "TOP" at the top. Re-position the
gasket and close the bottom flange
again; firmly tighten with screws. Mount
and tighten the bypass tube to the vessel to be monitored with process connection and seal.
Normally it is sufficient to fix the complete NBK with both process connections. However should the NBK be subjected to constant shock or strong vibrations it is recommended that the instrument is secured with rubber-damped
tube clips.
The bypass tube should never be
welded.
Mount and tighten the magnetic roller
indicator - if not already mounted - on
the bypass tube with the two
accompanying ribbon clamps.
Mount and tighten the reed switch - if
available and not already mounted - on
the bypass tube at the opposite side of
the roller indicator with the
accompanying ribbon clamp (ex contact:
2 ribbon clamps).
The height of the switch contacts may
be selected at will. The cable connection
must point downwards. Tighten the tube
clips until the gap cannot be closed any
further. The switch must be snug
against the stand tube. The switching
function of the switch is impaired by an
enlarged air gap.
Mount and tighten remote sensor - if
available and not already mounted - on
the bypass tube with the ribbon clamp.
The remote sensor must cover both
process connections fully. The cable
terminal box is situated at the top.
Page 6 NBK-M K03/0717
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