Flameproof Temperature Sensors

When it comes to installing temperature sensors such as thermocouples or resistance thermometers in hazardous areas, many companies do not fully understand or aren’t aware of product certification requirements and the new ATEX harmonised standards.

All OMC products have now been upgraded and are fully certified to the latest ATEX harmonised standards. If engineers install the latest Hart and digital fieldbus transmitters (e.g. a Yokogawa YTA 110 and YTA 320), care should be taken to ensure that approval of the complete assembly is certified, not just the transmitter. The integral transmitter and housing should carry its own certification and the temperature sensor coupled to this should also carry its own certification or be glanded to the unit using an approved terminal gland.

To simplify installation, OMC has developed its FPN (flameproof nipple) range of thermocouple or RTD sensors. These units, which are pressure tested to 1,000psi, can be fitted to other manufacturers’ temperature transmitters, while still maintaining the spring loading feature and an IP66/67 rating, without requiring any compression glands to be fitted that would restrict movement of the sensor. By working with BASEEFA, OMC has achieved Exde IIC T6 certification for the FPN range.

When terminating mineral-insulated (MI) thermocouples and RTD sensors into suitably certified Exd or Exe enclosures, engineers also need to ensure that the terminal glands carry the appropriate certification. The glands themselves need to be approved for use with sensors rather than just for cables. This is because, unlike cables, a temperature sensor is not terminated at each end and so can have different fault conditions. OMC offers a comprehensive range of thermocouples and RTDs that are certified as combined units with their own range of termination glands, giving an overall certification of Exde IIC T6, greatly simplifying the whole compliance process for the customer. Okazaki.