Fischer TW85 – Explosion proof (ATEX) intrinsically safe thermometer

Fischer TW85 is intrinsically safe explosion proof resistance thermometer, suitable for installation in gas and dust hazardous area Zone 0, 1 and 2.


Fischer TW85 – Explosion proof, intrinsically safe resistance thermometer

pdf-imageResistance thermometer for explosion proof hazardous area Zone 0, 1, 2 (gas, dust), suitable for all media air and liquid, vibration resistant
Make: Fischer Messtechnik (Germany)
Model: TW85


Fischer TW85, resistance type thermometer is an intrinsically safe instrument for measuring temperature in fluids and gaseous as well as dusts. This thermometer consists of a protective sleeve with various process connections, a terminal head and – depending on model – an exchangeable gauge slide. All components in touch with process media are leak tested. Pt100 temperature sensors to DIN EN 60751 in tolerance classes A or B in 2, 3 or 4-wire circuit are used inside the protective sleeve.

Models with 2 measuring circuits are possible. To transfer measurement as standard signal (eg. 4~20mA) a transmitter can be integrated into the terminal head.
These resistance thermometers meet demands of equipment – group II categories 1/2 G and 1/2 D and / or 2G and 2D. They are suitable for usage in explosion hazardous areas zone 1 (gas) and Zone 21 (dust). The protective sleeve may extend into Zone 0, resp 20 if the wall thickness is > 1mm (separation of zones).

These resistance thermometers with intrinsic safety Ex ‘i’ are certified for electrical connection to intrinsically safe circuits category ib (usage for Zone 1 and 2, with separative element in zone 0) as well as category ia (for usage of sensing probe in zone 0, 1 and 2)

Fischer TW85 - explosion proof intrinsically safe resistance thermometer
Fischer TW85 – explosion proof intrinsically safe resistance thermometer

Conformity of Norms:

Fischer TW85 resistance thermometer confirms to:

  • EN 50014 2002 +A1+A2 1999
  • EN 50020 2002
  • EN 50281-1-1 1998
  • EN 50284 1999
  • EN 1127-1 1997

Directive TW85

  • Ex II 1 / 2 G EEx ia IIC T6
  • Ex II 1 / 2 D IP65 Tx °C

Key Specifications:

  • Measuring element:
    • gauge slide acc. to DIN 43762,
    • insertion tube stainless steel 1.4571,
    • resistance 1 or 2 Pt100 acc. to DIN EN 60751
  • Protective sleeve:
    • SD 1/ SD 2/ SD 7 like DIN 46763 form D,
    • Material 1.4571
  • Insertion tube: dia 11mm, 165 mm long,
    • material 1.4571
  • Connection: terminal head type BUZ / BUZH IP65 EN 60529
  • Max. media temperature: 450°C

Application / Industry:

  • Chemical process industries
  • Petrochemicals
  • Marine, shipping, ship building
  • Water, effluent treatment system