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Explosion-protected Thermostat ELTH-ATHf |
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Explosion-protected
surface-mounting Thermostat
ELTH-ATHf-Ex Series
EC type examination to ATEX Directive 94/9/EC
for explosive gas atmosphere Zone 1
and explosive dust atmosphere Zone 21
ELTH-ATHf-EX-2 temperature monitor
ELTH-ATHf-EX-20 fail-safe temperature monitor
Brief descriptionExplosion-protected surface-mounting thermostats in the ELTH-ATHF-Ex series control and monitor thermal processes. They can be used directly in the hazardous area (zone 1 and zone 21). The thermostats are available both as temperature monitor ELTH-ATHF-EX-2 and temperature monitor ELTH-ATHF-EX-20 (fail-safe). Ex thermostats operate on the principle of liquid or gas expansion. The electrical switchingdevice is a microswitch inside a flameproof enclosure. Ex markingII 2G EEx ed IIC T6 for explosive gas atmospheres II 2D IP65 T80°C for explosive dust atmospheres Explosion protectionII 2G Equipment group II, Category 2, Equipment for explosive gas atmospheres II 2D Equipment group II, Category 2, Equipment for explosive dust atmospheres Type of explosion protection:EEx ed IIC T6 EEx General requirements Euronorm EN 50 014 / VDE 0170 / 0171 Part 1 e Increased safety Euronorm EN 50 019 / VDE 0170 / 0171 Part 6 d Flameproof enclosure Euronorm EN 50 018 / VDE 0170 / 0171 Part 5 IIC Gas group T6 Temperature class IP65 T80°C Application in combustible dusts Euronorm EN 50 281-1-1 / VDE 0170 / 0171 Part 15-1-1 IP65 Protection to EN 60 529-IP65 T80°C Max. permissible surface temperature (use in combustible dusts) Switching actionTemperature monitor ELTH-ATHf-EX-2 and fail-safe temperature monitor ELTH-ATHf-EX-20 If the temperature at the probe exceeds the selected setpoint, the microswitch is operated through a mechanism, and the circuit is opened or closed. If the temperature falls below the selected setpoint (by the amount of the switching differential), the microswitch returns to its initial position. Self-monitoring facility on the fail-safe temperature monitor ELTH-ATHFEX-20 A failure of the measuring system, i.e. when the expansion liquid escapes, will cause the pressure under the diaphragm to drop, thus permanently opening the circuit. The thermostat canno longer be reset. If the probe cools down to a temperature in accordance with the control range table, e.g. below -20°C, the circuit will also open. The ELTH-ATHf-EX-20 is reset automatically.
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