Nanomass density sensor for gases

Cooperation between Endress+Hauser Flowtec AG and TrueDyne Sensors AG

The instrument for continuous gas density measurement directly in the process – Nanomass gas density sensor is the first instrument for precise measurement of gas density based on the revolutionary MEMS Coriolis technology. This is where Endress+Hauser Flowtec AG’s long-standing Coriolis know-how meets TrueDyne Sensors AG’s innovative microtechnology. For the first time, it is possible to continuously monitor parameters such as gas density or gas quality directly in the running process under economically attractive conditions. Nanomass gas density sensors can be easily integrated into any existing process infrastructure.

How density measurement works
The heart of the Nanomass Gas Density measurement system is a MEMS chip with a microchannel that is permanently resonated. The natural frequency of this oscillation depends directly on the mass or density of the fluid flowing through (e.g. gas). The higher the density of the fluid – and thus also its inertia – the lower the natural frequency of the oscillating microchannel. The oscillation frequency is therefore a direct measure of the fluid density.


Monitoring of gas mixtures

In many industries, huge quantities of gases and gas mixtures are not only produced every day, but also used for a wide variety of production processes. The exact measurement of gas quality plays an increasingly important role in process monitoring – especially the measurement of gas density. Nanomass Gas Density is a high-precision measuring instrument working with innovative MEMS technology that simultaneously measures gas density, pressure and temperature of the medium – around the clock. This opens up unique perspectives for safe and efficient process control:

  • Efficient monitoring of mixing processes – for example in the production of two-component gases for welding systems or other manufacturing processes using the integrated concentration package (optional)
  • Precise control of admixtures – for example, from air to fuel gas – to optimize the combustion process

1. Welding gas. 2. Gas mixer which mixes the gases used for welding. 3 The Nanomass density sensor from TrueDyne / Endress+Hauser Flowtec measures the density and pressure of the gas mixture directly in the process. If this deviates from the nominal value, the process can be interrupted immediately. 4. Thanks to the continuous quality control of the gas used, you can weld without rejects.

Biogas – quality monitoring


Monitoring of the final composition of the biogas with nanomass gas density sensor before feeding into the grid.

Customer benefit:

  • Quality improvement: Better understanding of the process through continuous monitoring.
  • Reduction of OPEX: Robust and maintenance-free measurement.

1. Delivery of biomass and preparation for further processing 2. The fermenter or bioreactor where the biomass is cultivated (fermented) under controlled conditions 3. Biogas treatment for feeding into the natural gas grid. After appropriate pressure increase and odorization (addition of the typical natural gas smell) the treated biogas is fed into the natural gas network. 4.Nanomass for quality monitoring. The biogas consists of 55 to 60 % methane (CH4), a high proportion of carbon dioxide (CO2) and a low proportion of other gases. By separating carbon dioxide and hydrogen sulphide, the biogas, which is processed to natural gas quality, is produced with a methane content of >96%.

Direct measured variables:

  • Density
  • Temperature
  • Pressure

Derived measured variables:

  • Reference density according to the ideal gas law
  • Average molar mass according to the ideal gas law
  • Concentration according to user-configurable model in the case of binary gas mixtures (optional))

Permitted media are the gases listed below with the following features:

  • Non-corrosive
  • Absolute humidity < 10 g/m³ (dew point < 11 °C)
  • Relative humidity (non-condensing) < 80 %
  • Concentration of helium < 50 ppm (pure helium is not permitted)

Permitted gases or mixtures of such gases:

  • Nitrogen (N2)
  • Oxygen (O2)
  •  Air
  • Carbon dioxide (CO2)
  • Neon (Ne)
  • Argon (Ar)
  • Krypton (Kr)
  • Xenon (Xe)
  • Hydrogen (H2)
  • Methane (CH4)
  • Natural gas (maximum permitted helium concentration: 50 ppm)
  • Ethyne (acetylene) (C2H2)
  • Ethene (C2H4)
  • Ethane (C2H6)
  • Propene (C3H6)
  • Propane (C3H8)
  • Butane (C4H10)
  • LPG (supplied as gas)

Other media may be used after individual clarification.

Measuring accuracy:

Base accuracy under reference operating conditions

Density (gases): ±0,1 kg/m³

In the case of field density calibration: ±0.05 kg/m³ (applies following field density calibration under process conditions)

Note: The relative accuracy of the density measurement increases with increasing system pressure.

Temperature (during density measurement): ±0,5 °C

Pressure (during density measurement): ±0,05 bar

Accuracy of outputs:

o.r. = of the measurement

In the case of analog outputs, take the accuracy of the output into consideration for the measured error.

Current output: Max. ±0.1 % o.r. or ±15 μA


Base repeatability under reference operating conditions

Density (gases): ±0,05 kg/m³

Temperature: ±0,25 °C

Pressure: ±0,02 bar

Response time:

500 ms

Ambient conditions
Permitted medium temperature:

-20…+60 °C

Permitted ambient temperature:

-20…+60 °C

If operating via the USB port: The operating temperature is limited to 0 to 60 °C.

Permitted storage temperature:

-20…+60 °C, preferably +20 °C

Permitted density measurement range:

0 to 30 kg/m³

Permitted process pressure range:

Max. 20 bar
Bursting pressure 80 bar (absolute)

Recommended max. flow for complete accuracy:

1 l/min


To prevent the micro-channel from clogging, it is advisable to install a filter upstream from the measuring device. The filter is included in the overlay.

  • Recommended filter pore size: ≤15 μm
  • Included filter in delivery: ¹⁄₄”-Swagelok in-line filter SS-4F-15


Due to the high operating frequency of the micro-channel, vibrations (<20 kHz) do not affect measuring accuracy.

Inlet and outlet runs:

Inlet and outlet runs do not affect the measuring accuracy.

Ambient conditions
Climate class:

DIN EN 60068-2-38 (test Z/AD)

Electromagnetic compatibility (EMC):

In accordance with IEC/EN 61326
Complies with emission limit for industry as per EN 550011 (Class A)

Shock resistance:

As per IEC/EN 60068-2-31


Aluminum, powder-coated
Windows material: Polycarbonate

Wetted parts, fluidic system:

Stainless steel:

  • 1.4404 (316L)
  • 1.4542 (17-4 PH)

BOROFLOAT® 33 glass
Ceramic (AI2O3)


4-20 mA connection:

  • Socket: Die-cast zinc, nickel-plated
  • Contact housing: Polyamide
  • Contacts: Brass, gold-plated

RS232 interface:

  • Socket: Die-cast zinc, nickel-plated
  • Contact housing: Polyamide
  • Contacts: Brass, gold-plated

USB port:

  • Socket: Polyester
  • Contact housing: Polyester
  • Contacts: Copper base alloy, gold-plated
  • Protection cap: Polyester

Power connection:

Socket: Brass, nickel-plated

  • Contact housing: Polyamide
  • Contacts: Brass, gold-plated

Pressure sensor connection:

  • Socket: Brass, nickel-plated
  • Contact housing: Polyamide
  • Contacts: Brass, gold-plated
Dimensions / design



103 mm x 157.5 mm x 62.5 mm³


Approx. 1.5 kg

Dimensions measuring channel MEMS chip:

160 x 200 μm (500 nl)

Degree of protection:


Fluidic interfaces
Fluidic interfaces:

¹⁄₄”-Swagelok pipe union

Electrical interfaces
Power supply cable:

Outer diameter: 3.5 to 5 mm
Number of cores: Min. 2
Cable resistance: 77.8 Ω/km at 20 °C
Shielding: Single shielding

Signal cable:

Shielding: A shielded cable is recommended. Observe grounding concept of the plant.

USB cable (optional):

Cable type: Mini USB, type B, Buccaneer; standard USB type A
Cable length: Max. 5 m

RS232 cable (optional):

Cable type: M12, 4-pin; D-Sub, 9-pin
Cable length: Max. 5 m
Transmission rate: 57600 Bd

Cable connection:

Power connection: M9, 2-pin (connector)
4-20 mA: M12, 4-pin (connector)
USB port (optional): Mini USB, type B (socket)
RS232 interface (optional): M12, 4-pin (socket)

Supply voltage:

Power connection: DC 8 to 30 V, the power unit must be tested to ensure it meets safety requirements (e.g. PELV, SELV)
USB port (optional): DC 5 V

Maximum power consumption:

400 mW

Certificates and approvals
CE mark:

The measuring system meets the legal requirements of the EC Directives. Endress+Hauser confirms that the device has been successfully tested by applying the CE mark.

C-Tick Symbol:

The measuring system complies with the EMC requirements of the “Australian Communications and Media Authority (ACMA)”.

CRN approval:

As an option, the measuring system can also be ordered with CRN approval (Canadian Registration Number).

Ex approval:

Information about currently available Ex versions (ATEX, FM, CSA, IECEx, NEPSI etc.) can be supplied by your TrueDyne Sensors AG sales contact on request. All explosion protection data are given in separate Ex documentation, which is available upon request.

Electromagnetic compatibility (EMC):

In accordance with IEC/EN 61326
Complies with emission limit for industry as per EN 550011 (Class A)

Other standards and guidelines:

EN 60529
IEC/EN 60068-2-6
IEC/EN 60068-2-31
EN 61010-1
IEC/EN 61326

Product design
1908_Produktaufbau_Nanomass_TrueDyne_Endress+Hauser Flowtec