NT 61-Z0-Atex
1 Introduction
1.1 Intended Use
The level switch is used to monitor levels and temperatures inside a tank. The measuring tube is inside the tank during the pro-
cess.
According to IEC/EN 60079-11, NT 61-Z0-Atex series level switches are simple electrical apparatuses without separate voltage
source intended for installation inside the tank.
When used in explosive areas this type may only be operated on intrinsically-safe circuits. When using intrinsically-safe connec-
tions they can be installed in Zone 1 explosive areas and the level or temperature be monitored in a Zone 0 environment. The in-
trinsically-safe power supply must be suitable for the zone. The limits inside these operating instructions must be observed.
Never the use level switches in highly flammable or corrosive liquids. The medium must not contain particles, particularly
metallic particles, to prevent deposits on the float or between the float and switching tube.
Before installing the level switch, verify the listed technical data meet the application parameters. Also observe the applicable
requirements of IEC/EN 60079-14.
Further check if all contents are complete.
Please note the specific values of the level switch when connecting and the correct version when ordering spare parts.
The explosion protection markings on the level switches are:
II 1G Ex ia IIC T4 Ga
II 1D Ex ia IIIC T70°C Da
1.2 Functionality
1.2.1 Fill level monitoring
The measuring tube is located inside the tank. The level contacts (bistable reed contacts) are located inside the measuring tube.
These are activated by a magnet inside the level switch float. This can switch signals used to display the fill level.
The contacts clip onto a perforated rail spaced as specified in the purchase order and cannot be moved.
1.2.2 Temperature monitor
The temperature of a fluid is monitored via bimetal disc thermostat inside the level switch tube. When a set temperature is
reached, a bimetal snap disk inside the thermostat is triggered, which opens or closes an electrical contact. A Pt100 temperature
sensor can optionally be used in place of the bimetal thermostat.
Please note the technical data in the appendix.
1.3 Type plate
Example:
Manufacturer
Serial no., item no., year of manufacture
Type designation
Bühler Technologies GmbH
10610799 KW: 18-2017 001
NT 61-Z0-2M12/...-...-...-ATEX
IECEx IBE 17.0020X
IBExU16ATEX1183 X
IECEx - CoC no.
IBExU no.
CE mark, no. of notified body
0158
1. Type plate:
2. Type plate:
2
Bühler Technologies GmbH
BE100028 ◦ 10/2017
