| Item | Value |
|---|---|
| Measured gases | |
| Measuring range | |
| Detection principle | catalytic combustion |
| Accuracy | |
| Resolution | |
| Response time | |
| Ingress protection | |
| Explosion protection | |
| Operating temperature | |
| Power supply | |
| Output signal |
Using the principle of reactive heat measurement, the Dräger Polytron SE Ex sensing head is a gas detector that continuously monitors flammable gas and vapors in the ambient air.
Wide temperature range
The Dräger Polytron SE Ex sensor head can be used in a temperature range of -50°C to +85°C and up to +150°C with the special HT type.
Two models
Both the Dräger Polytron SE Ex PR M and SE Ex LC M are available in two models with different connection housings. Ideal for outdoor applications, the large housing is fitted with side cable glands. The latter can also be screwed to the bottom of the sensor head.
Comprehensive explosion-proof protection
The Dräger Polytron SE Ex sensor head is marked II 2 GD 4 and complies with guideline 94/9/EC (ATEX 95) and is therefore suitable for use in potentially explosive air in Zones 1 and 2 as well as in Zones 21 and 22.
Measure the signal
The mV measurement signal (proportional to the gas concentration) is emitted by a fire-encapsulated gas sensor and evaluated in the control unit. This control, such as the Dräger REGARD Ex or the Dräger Polytron SE Ex, can be connected to the sensor head using a three-wire shielded cable several hundred meters long and is used to warn at dangerous gas concentrations.
Catalytic bead (Pellistor) sensor
A catalytic bead sensor contains a porous ceramic bead embedded with a thin platinum coil. The platinum coil current is approximately 270 mA, which heats the ceramic head to approximately 450°C and acts as a measuring resistor to precisely adapt to the temperature. The flammable gas molecules entering the sensor head are catalyzed oxidation during exothermic release. The increase in resistance of the obtained platinum coil is directly proportional to the gas concentration.
environmental conditions
If possible large fluctuations in ambient temperature are compensated for according to the measurement characteristics, the temperature rise (depending on the gas concentration) can only be used as a measurement signal. Therefore, the second catalytic bead sensor (as opposed to the catalytic sensor in the term) is used without a catalyst and therefore can only measure the ambient temperature. In the Wheatstone bridged circuit, the catalytic sensor compensates for environmental influences, especially the effects of ambient temperature.
Toxicity test reliability
Dräger catalytic sensors have been produced in-house for many years, PR type, and resistant to toxicity. They are designed to be more durable than conventional catalytic sensors found in industrial settings, which contain toxic catalysts such as sulfur, phosphorus, lead, or silicone compounds.
Draeger polytron ExFlammable gas detectors brochure
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It is suitable for industrial safety monitoring and on-site inspection scenarios.