NBK
page 6 NBK K01/0906
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 level in a tank or a mixer is continuously
displayed as a red column, even when the power fails.
Transmitter
To remotely transmit the level a transmitter with a chain of resistors or a magne-
tostrictive 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.
Universal indicating unit
A universal indicating unit of type series ADI can be mounted on the bypass to
display and evaluate the standard signal (4–20 mA) generated by the transmitter.
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
The bypass level indicators can be supplied with ATEX approval. As an option
limit contacts and a reed contact chain with ATEX approval are available for level
measurement and monitoring.
ATEX approval:
Bypass-level indicator: Ex II 1G /2GD (mechanical)
Limit contact NBK-RA: Ex II 2G EEx m II T6 / T5
Immersible magnetic probe
(Reed contact chain): Ex II 1G EEx ia IIC T6
Transmitter for Reed chain: Ex II (1) G [EEx ia] IIC
GL version
In the pressure stages PN 16 (NBK-03) and PN 40 (NBK- 06) the bypass level
indicators are available with GL approval (Germanischer Lloyd). The magnetic
roller indication as well as limit contacts and a reed contact chain can be
delivered for level indication and evaluation .
Certificate-No. GL: 79 786-95 HH
