Our Products

MEMS offers two complementary gas quality sensor product lines - both designed as maintenance-free, inline gas measurement solutions for industrial applications.

gasQS™ static

The gasQS™ static determines gas composition by measuring thermal conductivity - compact, maintenance-free, and ready to use in seconds.

gasQS™ flonic

The gasQS™ flonic measures three physical properties and uses them to calculate calorific value, heating value, density, H₂ content, and Wobbe index - without requiring knowledge of the gas composition.

It is can be advantageous to combine both the gasQS™ static and the gasQS™ flonic - depending on the application.
See Applications

gasQS™ static

Precise inline measurement for binary and quasi-binary gas mixtures

Screw in, connect, measure. The gasQS™ static is our most compact gas quality sensor - developed for fast and high-precision inline measurement of binary and quasi-binary gas mixtures.

 

Outputs
  • Gas concentration (e.g., H₂-content, CH₄ in biogas, H₂ in natural gas)
  • Methane number (MN CAT or AVL)
  • Calorific value (CV)
  • Relative density
Fast response time
  • T90 < 2 seconds
Certified for explosion-hazardous areas
  • Intrinsically safe in Zone 0 (Ex II 1G Ex ia IIC T4 Ga)
Maintenance-free - with no ongoing operating costs
  • No calibration required
  • No carrier gases
  • No moving parts
  • High chemical resistance
  • Exceptional long-term stability
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Thanks to the simple screw-in installation, only minimal interventions in the pipe system are necessary - no exhaust line required. The standardised 4-20 mA output signal enables uncomplicated integration into existing control systems. A true plug-and-play solution.

gasQS™ static- applications

Thermal conductivity is precisely determined using a micro-thermal sensor. Thanks to its high sensitivity, the sensor is ideally suited for detecting changes in the gas composition of gas mixtures with more than two components. Unlike standard devices on the market, this robust, compact, and unobtrusive device requires neither recalibration nor a reference gas. The two-wire connection allows for easy integration into the control system without requiring knowledge of the bus topology. The simple screw connection requires only minimal intervention in the piping system and does not require an exhaust pipe. The instrument is pressure-compensated and therefore independent of the prevailing process pressure.

The two-wire connection allows for easy integration into the control system without requiring knowledge of the bus topology. The simple screw connection requires only minimal intervention in the piping system and does not require a vent line.

The measuring instrument is pressure-compensated and therefore independent of the prevailing process pressure.

gasQS™ static - datasheet

The gasQS™ static continuously and accurately measures the thermal conductivity of gases using an integrated microthermal sensor. This allows for reliable determination of both hydrogen purity – for example, by detecting impurities such as nitrogen, oxygen, or methane – and the hydrogen concentration in gas mixtures such as natural gas or methane.

Unlike many conventional methods on the market, the device does not require calibration with reference gases and contains no moving parts – ensuring maintenance-free, long-term stable measurement.

Thanks to its compact design and simple two-wire connection, the device can be quickly integrated into existing control systems. The screw-in mounting allows for direct installation in the pipeline - without gateways or knowledge of bus topology.

gasQS™ static H₂ - datasheet

The gasQS™ static uses an integrated microthermal sensor for precise and continuous measurement of the thermal conductivity of gas mixtures. In typical biogas applications - methane in carbon dioxide - it enables the precise determination of the mixing ratio and thus reliable process monitoring.

Unlike conventional systems, the gasQS™ static is compact, robust, and maintenance-free - requiring no calibration with reference gases and containing no moving parts.

Its pressure-compensated measurement, direct screw-in installation, and simple two-wire connection without gateways allow for quick integration into existing systems – with no complex modifications or bus topology knowledge needed.

The gasQS™ static is the smart solution for precise, maintenance free, and long-term stable biogas measurement.

gasQS™ static Biogas - datasheet

The gasQS™ static precisely and continuously determines the thermal conductivity of gas mixtures using an integrated microthermal sensor. For applications in the field of energy-efficient ammonia transport, the gasQS™ static monitors the cracking process in real time and reliably analyzes the resulting H₂/N₂ mixture.

In contrast to conventional measurement systems, the device is compact, robust, and maintenance-free – it requires no calibration with reference gases and contains no moving parts. The fast T90 time in the second range is crucial for monitoring cracking efficiency and protecting downstream components such as fuel cells.

The pressure-compensated measurement and simple two-wire connection enable rapid integration into hydrogen infrastructures - without complex gateways. The gasQS™ static is the robust solution for stable process control in the sustainable hydrogen economy.

gasQS™ static Ammonia- datasheet

gasQS™ flonic

The cost-effective alternative to a gas chromatograph

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The gasQS™ flonic is a versatile gas quality sensor for monitoring and controlling gas-powered machinery and for energy billing in natural gas distribution networks. For operators looking for a cost-effective alternative to gas chromatographs, the gasQS™ flonic delivers equivalent gas composition analysis - including calorific value, Wobbe Index, and methane number - at a fraction of the cost and complexity, with no carrier gases required.

Specifically, our gasQS™ flonic NGis OIML certified so it can be used for billing on the gas grid.

     

    Outputs:
    • Gas density (norm density and relative density to air)
    • Higher and lower calorific value
    • Upper and lower Wobbe Index
    • Methane number (AVL)
    • Compressibility factors
    • Hydrogen content (H2 mol%)

    Typical applications include natural gas distribution, gas engines and turbines, LNG installations, fuel cell systems, industrial burners, and power-to-gas (P2G) plants.

    Featuring:
    • Direct calculation of gas properties from multiple parameters
    • Compact design with low energy consumption
    • Modbus connectivity for easy integration
    • Reliable long-term operation without maintenance

    The analyzer is designed for reliable operation in the field. It operates as a standalone device without carrier gases. If used for billing, it requires only a simple methane calibration once every 12 months.

    gasQS™ flonic- common applications

    The gasQS™ flonic Z1 is custom-designed for industrial gas quality measurements without billing requirements - precisely calibrated for the specific application, with freely selectable output parameters.

    Using a microthermal CMOS sensor, a critical nozzle, and two valves, it simultaneously measures thermal conductivity, heat capacity, and speed fo sound velocity - and uses these to calculate, in real time, the gas parameters defined by the customer, such as:

    • Lower heating value and gross calorific value
    • Density and Wobbe index
    • Methane number and H₂ content

    The gasQS™ flonic Z1 is ideally suited for:

    • Gas engines and gas turbines
    • Biogas plants and grid feed-in
    • Power-to-gas and hydrogen applications
    • Industrial burners and fuel cell systems

    The integrated Modbus interface enables direct integration into existing control systems.

    The device operates completely autonomously - without carrier gases or calibration gas.

    gasQS™ flonic Z1 - datasheet

    The gasQS™ flonic NG is the OIML R140-certified version for metrology-compliant energy billing in gas distribution networks - the approved alternative to gas chromatographs for billing stations. Using a microthermal CMOS sensor, a critical nozzle, and two valves, it simultaneously measures thermal conductivity, heat capacity, and speed of sound - and calculates all relevant gas parameters for billing and network monitoring from these values. Tests and evaluations were conducted by NMi in accordance with OIML R140; certification was granted under WELMEC 8.8 for use in systems subject to the Measuring Instruments Directive (MID).

    The device is an in-house development by Mems AG. Thanks to a deep physical understanding of the individual components and their interactions, customer-specific applications can be flexibly implemented. The gasQS™ flonic NG offers a complete, ready-to-use solution - optimally tailored to the respective customer application and with significantly lower investment and operating costs than a gas chromatograph. For metrology-compliant billing, only a simple methane calibration once a year is required.

    gasQS™ flonic NG (H) - datasheet
    gasQS™ flonic NG (L) - datasheet

    The gasQS™ flonic is also available in a high-pressure version - for operating pressures up to 200 barg.

    In this configuration, a gasQS™ flonic Z1 or NG is integrated into a cabinet and equipped with an upstream pressure reducer. This enables precise gas measurements even in locations where pressure reduction prior to measurement was previously unfeasible or economically unviable.

    Typical applications:

    • High-pressure gas pipelines and transfer stations
    • Compressor and storage facilities
    • Industrial processes with elevated operating pressures

    All the benefits of the gasQS™ flonic are fully retained - maintenance-free, without carrier gases, and with the same measurement accuracy as the standard version. We are happy to assist you in selecting the appropriate model and pressure rating.

    gasQS™ flonic HP - datasheet

    FAQ - Frequently asked questions

    Regarding our gasQS™ products

    gasQS™ static

    How does the gasQS™ static work?

    The gasQS™ static uses an integrated microthermal CMOS sensor to measure the thermal conductivity of a gas mixture continuously and precisely. From this measurement, it derives gas quality parameters such as methane content, hydrogen concentration, or calorific value. The measurement is pressure-compensated, requires no gas flow through the device, and no carrier gases.

    Does the gasQS™ static require calibration?

    No. The gasQS™ static is factory-calibrated and requires no field calibration or reference gases during operation. It has no measurable drift documented over more than 8 years of continuous field operation. No maintenance is required during normal use.

    What gas mixtures can the gasQS™ static measure?

    The gasQS™ static is available in several calibrated variants: Biogas (CH4 in CO2, 40–100 mol%), MG for multi-component gas mixtures including natural gas and hydrogen blends (H2 in natural gas 0–100 mol%, ±0.5%), and H2 for hydrogen purity monitoring (H2 purity in N2/O2 at ±500 ppm; H2 in methane 0–100 mol%, ±0.1%). An Ammonia variant is also available for cracking applications. Custom calibration ranges are available on request.

    Does the gasQS™ static need a gas flow to operate?

    No. The gasQS™ static continuously measures the gas quality at the sensor face with no flow through the device. It installs directly inline via a G 3/8\" male thread screw-in connection.

    What is the response time of the gasQS™ static?

    The measuring time is 0.1 seconds with a 1-second measurement interval. T90 response time is typically 2 seconds, enabling real-time process monitoring and control.

    Is the gasQS™ static suitable for use in hazardous areas?

    Yes. The gasQS™ static is ATEX and IECEx certified for Zone 0 hazardous areas: II 1 G Ex ia IIC T4 Ga (IECEx SEV 22.0008X; SEV 15 ATEX 0191 X). Gas group IIC covers hydrogen and the most demanding explosive atmospheres.

    Can the gasQS™ static measure hydrogen in natural gas?

    Yes. The gasQS™ static MG measures hydrogen content in natural gas over a 0–100 mol% range with ±0.5% accuracy. The background natural gas composition must be known and reasonably stable - it is specified at order and used for calibration. For variable base gas compositions, two units can be deployed in a differential configuration (one upstream, one downstream of the H2 injection point) to achieve ±0.2 mol% accuracy.

    Does nitrogen or oxygen in the gas affect the measurement accuracy?

    For biomethane and biogas applications, N2 and O2 cause a small systematic positive offset on the CH4 reading. At 1% N2 or O2, the reading is approximately 0.4% too high. For safety monitoring applications with ±2% tolerance, N2/O2 levels up to around 2% remain acceptable. If the N2/O2 concentration is independently known, mathematical correction of the reading is possible. For hydrogen content measurement in natural gas, N2 and O2 variations do not cause meaningful interference.

    What is the operating pressure range of the gasQS™ static?

    The standard supply line pressure range is -0.5 to +9.0 bar gauge. An extended range up to +15.0 bar gauge is available on request and must be specified at order. The mechanical load limit of the supply line is +30 bar gauge. Pressures above 15 barg are possible for special projects but require specification at order time.

    What output signal does the gasQS™ static provide?

    The gasQS™ static outputs a standard analog 4–20 mA signal via an M12-B, 5-pole connector. One output value per device. Modbus RTU, Profinet, and Modbus TCP are not supported on the static - for digital bus communication, the gasQS™ flonic should be considered.

    gasQS™ flonic

    How does the gasQS™ flonic work?

    The gasQS™ flonic uses a microthermal CMOS sensor combined with a pressure sensor and a critical nozzle to measure three physical properties of the gas: thermal conductivity, heat capacity, and speed of sound. These three measurements feed into a correlative model to derive gas quality parameters including calorific value, Wobbe index, density, methane number, compressibility factors, and hydrogen content. Each instrument is individually factory-calibrated. No carrier gases are required.

    What gas quality parameters does the gasQS™ flonic output?

    The flonic Z1 can output: norm density (±0.4%), relative density (±0.4%), gross calorific value Hs (±1.0%), net calorific value Hi (±1.0%), upper Wobbe index Ws (±1.3%), lower Wobbe index Wi (±1.3%), methane number (±3.0%), hydrogen content 0–50 mol% (±1.0%), and compressibility factors Z and Zn (±0.5%). Up to 14 output values are configurable via Modbus registers. The flonic NG is additionally certified under OIML R140 for fiscal use, with calorific value accuracy of ±1% (Class B).

    Is the gasQS™ flonic suitable for fiscal gas metering?

    Yes, the gasQS™ flonic NG is certified for fiscal gas metering under OIML R140 Class B (NMi certificate TC12470, MID Directive). It is also certified by LNE in France. Certified outputs include gross calorific value, gas density, and compressibility factors. An annual single-point adjustment with pure methane (approx. 20 minutes) is required. The flonic Z1 uses identical measurement technology but is not fiscally certified, offering more flexible outputs.

    How often does the gasQS™ flonic need to be calibrated?

    The flonic Z1 (non-certified variant) requires no calibration - and so, has effectively zero OPEX in practice. The flonic NG (fiscally certified variant) requires one adjustment per year, taking approximately 20 minutes. The only consumable needed is pure methane (≥99.995%). PC software for the adjustment procedure is provided by Mems AG.

    Can the gasQS™ flonic measure hydrogen in natural gas?

    Yes. The flonic Z1 measures hydrogen content in natural gas and H2/NG blends up to 50 mol% H2 with ±1.0% accuracy. The flonic NG covers H2 up to 23 mol% as a non-certified additional output. For hydrogen purity applications up to 100 mol% H2 in any gas mixture, the flonic HP variant is available.

    Is the gasQS™ flonic certified for hazardous areas?

    Yes. The gasQS™ flonic is ATEX and IECEx certified: Ex II 2G Ex ib IIC T4 Gb (IECEx SEV 22.0007X; SEV 18 ATEX 0111 X) for Zone 1. Gas group IIC covers hydrogen and the most demanding explosive atmospheres.

    How much gas does the gasQS™ flonic consume?

    The flonic takes one discrete gas sample per measurement cycle of 0.03 ln. The internal valve closes between cycles - there is no continuous gas flow. This is fully compliant with the EU Methane Regulation (2024/1787). Sampled gas is typically vented to atmosphere; it can alternatively be returned to a low-pressure network, reducing emissions to zero.

    How does the gasQS™ flonic compare to a gas chromatograph?

    The gasQS™ flonic is a cost-effective alternative to gas chromatographs for real-time gas quality monitoring. It requires no carrier gases, has no moving parts, needs no complex sample conditioning, and provides continuous measurement with a 30-second cycle time. While a GC provides full component analysis, the flonic's correlative approach delivers the derived parameters most customers actually need - calorific value, Wobbe index, density, methane number - faster and with significantly lower maintenance and operating costs.

    What is the measurement interval of the gasQS™ flonic?

    The minimum measurement interval is 30 seconds. The interval is programmable upward (e.g. 60 s, 90 s). T90 response time is within 3 measurement intervals. This makes the flonic well suited for continuous process monitoring where fast response is needed but sub-30-second cycles are not required.

    What communication protocol does the gasQS™ flonic use?

    The gasQS™ flonic outputs via Modbus RTU (EIA-485 2-wire RS485). Up to 14 output values are configurable across 16 Modbus registers. A bus converter for customised bus profiles is available as an optional accessory. Supply voltage is +12.0 VDC ±10%.