The DrägerSensors ... DQ are based on the catalytic bead detection principle. The most important component are the hot, catalytically active pearls on platinum coils (pellistors). These pellistors burn the gas and additional heat of reaction is created. The temperature increases depending on the gas concentration and thus also changes the electrical resistance of the platinum coils. This change is passed on as a measuring signal. There are five different catalytic bead sensors from Dräger, which are used in different transmitters and measuring heads.

PR stands for poison resistant. The pellistors of the DrägerSensor PR M DQ have a longer service life under the influence of poisonous substances. The sensor has a metric thread (M) on the back.

The DrägerSensor PR NPT DQ also withstands poisoning substances for a long time. This sensor is equipped with a NPT thread on the back.

The DrägerSensor HT M DQ can be used at ambient temperatures of up to 155 ° C and is also approved accordingly (HT = high temperature). This sensor also has a metric thread.

​LC stands for >low concentration<. The DrägerSensor LC M detects very low gas concentrations in the measuring range from 0 to 10% LEL. This is possible by a special arrangement of the PR pellistors, as well as an amplifier electronics. The sensor has a metric thread.

​The LC NPT sensor also detects gas concentrations in the measuring range of 0 to 10% LEL. It is equipped with a NPT thread.