Dräger Sensor for Fixed Gas Detector

The sensor is the most important component inside a gas detector. The gas detector sensor converts the measured variable, e.g. a gas concentration, into an electrical signal. Depending on the gas sensor type, this is achieved by either chemical or physical processes. Dräger offers a wide range of different gas detector sensors for fixed gas warning systems.

1. Electrochemical Dräger Sensor

Fast response, high accuracy, great stability, long life. Electrochemical DrägerSensors offer all these benefits. You can use the robust and long-life sensors for the selective measurement of the smallest concentrations of toxic gases and oxygen in ambient air.

The electrochemical are designed to provide a reliable und stable measurement function over a long period of time. The use of resistant plastics, such as PTFE, and the purest catalysts make this possible. Additionally, a huge electrolytic reservoir and large electrode areas provide sufficient reserves for a long lifetime. The construction of the Dräger Sensors offers you long stability and a low age-related drift.

All DrägerSensors are factory calibrated with the target gas. These values are saved in the internal, electronic memory. You can use the sensors in the field immediately. For some sensors other tagret gases can be selected from the internal gas library.

All sensors have an internal temperature sensor. Between -40°C and +65°C, the temperature influence is compensated for zero and sensitivity. The patented internal pressure compensation balances adverse ambient conditions, such as humidity changes or barometric variation. Due to this fact, you can use the sensors even in high or low pressure. For some sensors you can reduce the disturbing influence of cross-sensitivities by combining selective filters.

Performance features
- Low detection limits
- Optimised selectivity
- Excellent accuracy of measurements
- Fast response
- Comprehensive self-diagnosis options
- It is possible to choose between oxygen sensors for partial pressure measurement or volume percent measurement
- Sensors with organic electrolyte for detection limits in lower ppb range
- Acid gas sensor AC with unlimited lifetime, due to refillable electrolyte.

2. Catalytic Bead Dräger Sensor

The Dräger Sensor ... DQ detects flammable gases and vapours such as hydrogen. Due to the double-detector compensation method, the catalytic sensor is particularly long-term stable. The wire mesh at the gas inlet serves as a flame barrier. So it ensures explosion protection at the same time short response time.

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 Dräger Sensor 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.

3. Dräger Sensor IR

Upgrade from Catalytic bead to infrared technology with ease using the DrägerSensor IR. The Sensor IR can replace catalytic ex-sensors (pellistors) from the majority of manufacturers without replacing controllers, cables, junction boxes or control systems.

With its Wheatstone bridge emulation, the Sensor IR outputs a mV signal, the same as the pellistor it replaces. The result is the control system sees the same signal input as before the Sensor IR was installed.
Naturally the Sensor IR can be operated with all Dräger control systems, more importantly it can also be connected to almost all installed systems from other manufacturers, without having to modify the wiring.

The Sensor IR offers a gas library with three gas categories: methane, propane and ethylene. Therefore, nearly all hydrocarbons are detectable. Temperature-compensatory linearising algorithms allow signal outputs for individual substances.
Through optional accessories e.g. the process adapter or the duct mount set a multitude of measuring tasks can be performed professionally.

Technological advantages in infrared technology (e.g. fail-safe operation or immunity against pellistor poisons) have been recognised and valued by gas detection users for a long time.
The Sensor IR now also offers these plus points for systems that have already been installed. Its long life time of over 15 years and long maintenance intervals mean that maintenance costs are significantly lower than for pellistors, make it a cost-effective, premium solution.

Performance
- Temperature-compensatory and non-imaging optics
- Gas library with 3 gas categories: Methane, propane and ethylene (typical of most hydrocarbons), performance approved in accordance with IEC 60079
- Performance approval (in accordance with IEC 60079) for 13 further substances
- Dirt and dust protection through hydrophobic splash guard
- mV signal for Wheatstone bridge installations
- Specified temperature range from - 40 °C to + 65 °C / - 40 °F to + 149 °F
- Unrestricted usage in humid atmospheres
- Hermetically sealed enclosure made of 316 stainless steel
- Slim enclosure design for confined areas of use
- Long maintenance interval thanks to minimum long-term drift
- No moving parts
- Typical life time: 15 years
- Ex approvals for worldwide use: ATEX, IECEx, UL, CSA
- Dust ex approval for zone 21 and 22
- Ingress Protection: IP 65, IP 66 and IP 67