Dräger Gas Sampling Solutions

Dräger specialises in the engineering of individual gas sampling solutions for a wide range of different applications. In certain applications, the use of conventional gas detector and sensors may be limited. This may be caused by the environment in which the device needs to be place, the cable routing or even access restrictions. There may also be significant cost implications with installation of these devices.

Gas sampling solutions, or aspirated gas detection system, operate by drawing a gas sample from the desired detection point to a remotely located detector. Typically, the sample is drawn through tubing and some kind of pump is used to move the sample gas stream.

There are typically four main component of a gas sampling system; Sampling, Transport, Measuring and Data Monitoring. Find out more about what makes a system below.

Sampling

Sampling is an essential step between the process site and the detection point. The use of suitable filters removes fluids or particles in the gas sample, which could otherwise lead to cold spots or damage in the sampling line.

Quality of detection

They can also have a negative effect on the quality of detection at the measurement point itself. A suitable material for the sample pipework is essential to maximize the lifetime of a system. This is especially important for corrosive substances. The sample tubing shall be suitable for the environmental conditions and the defined Ex area.

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Transport of the gas flow

Extractive gas analysis needs an effective treatment of the gas flow in the pipes to maintain the composition of the target and guarantee high-quality detection results. Unwanted effects like deposits, condensates in the pipes or diffusion through the lines, which can damage the fittings, pipes and tubes must be reduced to a minimum or wholly avoided. The correct conditioning methods; cooling, filtering, heating or condensing of the process gas is essential for providing optimum detection results and prolonging the life of the system.

A critical part of the system

A pump must be used if the pressure difference is insufficient to transport the gas from the process site to the detection (analyzer) point. A gas sampling system can be equipped with an Ex or non-Ex membrane pump, operated by a brushless DC motor to provide a continuous sample.

Careful selection required

A pumped system also allows gases to be drawn from areas with under pressure. The type and material of the pump have to be selected to suit the gas properties, gas flow and pressure conditions. In many applications, the gas is corrosive or has challenging characteristics, requiring careful selection of an appropriate pump and associated fittings.

As an alternative to the membrane pump an aspirated system driven with pressurised air may be used. These systems, typically require less maintenance than a pumped system.

Effective treatment of the gas flow

Extractive gas analysis needs an effective treatment of the gas flow in the pipes to maintain the composition with the target and guarantee high-quality results of the analysis. Unwanted effects like deposits, condensates in the pipes or diffusion through the lines, which can damage the fittings, pipes and tubes must be reduced to a minimum or wholly avoided.

The correct conditioning methods

The correct conditioning methods; cooling, filtering, heating or condensating of the process gas is essential for a long lifetime of the system and optimum detection results.

Measuring

In gas sampling systems, once the gas conditioning has been completed, it is passed to the detection system. There are specific methods available for different applications and targets.

Different applications and targets.

In gas detection applications and different industrial fields, we have a wide experience in detecting gases and vapours such as safety monitoring and process gas measurement. The method used depends on gas type, concentration, compositions and conditions in the pipe.

Data monitoring

When operating a system, multiple parameters must be monitored to ensure accurate interpretation of the gas sampling system. This guarantees the correct operation of the system and the process. These parameters include; gas concentration, temperatures and gas flow.

Access to information

The safety control unit can be combined with the existing gas detection system to allow the operator access to this information along with many other safety parameters including:

Real-time trend view of the gas concentration with the visualisation software
Status information of the devices (Inhibit, warning signals, gas name & values)
Remote data logging of gas levels and alarms on both timed intervals and events
Alerts via SMS or Email to dedicated key personnel
Multiple data outputs are possible

Gas Sampling Applications

There are many scenarios and applications where Gas Sampling situations can be deployed. We've listed just a few of them below. Simply click on the title (or small blue arrow) to find out more.

Crank case application (Shipping industry)

On LNG powered ships, the crank case housing can be monitored for liquid gas penetrating from the reaction chamber. A sampling system with an infrared gas detector for hydrocarbons in the crank case housing would be a typical solution. Methane can be drawn by an aspirator into the measuring cuvette of the detector and monitored in LEL %. A safety controller monitors the signals from the gas transmitter and the volume flow monitoring and can switch off the motor if a critical concentration is reached.

Conveyor Dryer application (General Industry)

Belt dryers can used to dry foils, in such a way that the used organic solvent is withdrawn . An air flow which is passed over the foils, evaporates the solvent. These solvents typically have a high vapor pressure and come out of the product very early in the primary drying phase. The solvent concentrations in the stream can be monitored with a sampling system. If the concentrations are too high, the drying air flow can be reduced with a control system, thereby saving hereditary amounts of energy. Suitable gas detectors are IR gas detectors with a gas library which, depending on the application and the associated solvent formulation, can be specifically adjusted to the solvent and the concentration.

Fuel cell (Energy Industry)

Most fuel cells are powered by hydrogen, which can be fed to the fuel cell system directly or can be generated within the fuel cell system by reforming hydrogen-rich fuels such as methanol, ethanol, and hydrocarbon fuels. In this case the methanol fuel was used as part of a test system. The potential for leaks to occur around the test system required local detection which could not be achieved with point gas detectors. A gas sampling system, controlled via a PLC, was designed to sequentially sample from around the fuel cell and utilised an IR detector to monitor the for possible methanol leaks.

Piping leakages (Chemical Industry)

Gas transport in area that are difficult to access, such as underground tunnel systems, should be checked regularly for gas releases. Gas sampling systems can be used to extract samples from various compartments of the tunnel system and monitor for the presence of potential gases. This can happen sequentially which allows for a large number of areas to be monitored whilst reducing the number of detectors required. Pairing the system with a PLC to control the sampling rates and a gas detection system, including detector and controller, allows effective monitoring, appropriate alarm and action initiation along with data recording of any events.

Gas Sampling Enquiry?

It is essential to understand customer process conditions to create the best solution to the various application needs. If you have a specific application in mind or would like to discuss further, please complete the short form below and one of our gas sampling experts will be in touch as soon as possible.