Gas Analyzers and Gas Sensors

What is a Tunable Diode Laser analyzer (TDL analyzer)?

Tunable diode laser analyzers are systems for measuring the concentration of specific species within a gas mixture using laser absorption spectrometry. Simply put, a laser beam, tuned to identify a particular gas species, passes through the gas to a detector. The presence of this gas in the stream causes light absorption and reduced signal intensity. The light collected at the detector is detected by a photodiode and analyzed to quantify the gas concentration.

TDL analyzers are rapidly replacing other technologies in process plants because they offer increased productivity, capacity upgrades and higher safety.

How can I reduce maintenance and installation costs with a TDL analyzer?

Installing a TDL analyzer for in situ gas analysis allows you to eliminate the sample conditioning system that is required with standard extractive techniques. In addition, due to the one-flange, folded path concept showcased by METTLER TOLEDO's GPro 500 Gas Analyzer, you can further reduce the installation and maintenance costs related to typical TDL analyzer alignment.

What gas species can be measured with a TDL analyzer?

METTLER TOLEDO GPro 500 Gas Analyzers offer measurement of carbon monoxide (CO%), carbon dioxide (CO₂%), hydrogen chloride (HCl), hydrogen sulfide (H₂S), gaseous oxygen (O₂) or moisture. We are continuously expanding our offering of parameters to support industry needs.

What are some suitable applications for a TDL analyzer?

TDL gas analyzers are used in a wide range of applications across a variety of industries. Installations are common in chemical industries, petrochemical refining, pharmaceutical manufacturing, and food and beverage production.

In industries such as chlor-alkali, TDL analyzers can replace traditional measurement systems for moisture monitoring to prevent compression system corrosion.

A GPro 500 with a filter probe adaption is optimal for combustion applications where high dust loads could typically obstruct measurement. This setup is particularly appropriate for fired heaters and boilers.

In inerting and blanketing applications, the use of a non-purge probe provides increased safety and reduces running costs.

For in situ gas measurement in DN50 or 2" pipes when you have high or low velocities or where you wish to avoid flow restrictions, the GPro 500 Wafer Cell adaption provides stable measurement.

What is an amperometric oxygen gas sensor?

Amperometric, or polarographic oxygen sensors are sensors for measuring gaseous oxygen using an oxygen permeable membrane and an electrochemical anode/cathode assembly. These sensors are good for gas monitoring in applications such as nitrogen blanketing and off-gas monitoring.

Amperometric gas-phase oxygen sensors provide fast measurements and are quick and easy to replace, calibrate and maintain.

How often do I need to service an amperometric gas sensor?

The inner body of an amperometric gas sensor requires occasional replacement. More frequently, the electrolyte in the sensor's membrane body will need replenished and the membrane body itself, replaced. Replacement/refilling times vary based on individual application conditions and knowing when to conduct these tasks is often down to the experience of operators.   

METTLER TOLEDO's amperometric gas sensors with Intelligent Sensor Management (ISM) technology offer diagnostic tools that show, in days remaining, when inner body and membrane body replacement or electrolyte refilling should be performed. These tools, such as the Dynamic Lifetime Indicator, help to ensure that you avoid any unplanned downtime in your monitoring and control processes.

How often do I need to calibrate an amperometric gas sensor?

Calibration intervals are difficult to calculate, but ISM technology will give you an estimate based on the conditions of the process the sensor is operating in. The Adaptive Calibration Timer (ACT) provides an accurate calculation for when you should plan to calibrate your gas sensor, meaning less unplanned downtime or process interruptions.