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Gas Density Sensor

For accurate, inexpensive, in-situ gas measurement in variety of metals heat treatment applications

Air Products’ patented gas density sensor is beneficial for accurate, inexpensive, in-situ measurement in a variety of metals applications. Knowing the density of a mixture of two gases, such as hydrogen and nitrogen in sintering, brazing, and annealing furnaces, allows direct calculation of the composition. Installed directly in furnaces, pipeline systems, or continuous sampling lines, the sensor provides real-time measurement of your atmosphere or shielding gases. Data from these sensors enables optimization of gas consumption, improvement in quality, consistency, and productivity, and documentation of compliance with industry standards. This SMART system features Air Products’ Process Intelligence—our IIOT (Industrial Internet of Things) driven approach to process optimization, applying decades of experience in gas supply, applications knowledge, and safety.
Download Gas Density Sensor optimizes furnace efficiency data sheet

For Accurate, Inexpensive, In-situ Gas Measurement in Heat Treating

  • Convert density measurements to gas composition for binary mixtures
  • Install in gas mixture piping, in-situ in furnaces, or in furnace atmosphere sampling lines
  • Fast response for real-time measurement
  • No reference gas needed
  • Enables IIoT (Industrial Internet of Things) connectivity with your processes
Data from these sensors enables you to:
  • Optimize gas consumption
  • Improve quality, consistency, and productivity of your parts and materials
  • Document compliance with industry standards (e.g. CQI-9 and NADCAP)
  • Record production data for documentation

Get in touch with our technical experts.

Let us help you optimize and monitor your operation with gas density sensors.


Ask the Expert

Liang He

Fémfeldolgozó K+F mérnök, Észak-Amerika

“Why is control necessary for a protective atmosphere?”
The simplest nonreactive atmosphere for thermal processing of a metal or material is a pure inert gas or vacuum, yet neither offers protection against trace impurities such as oxygen, water, and carbon dioxide, which are almost invariably present in the heat treating furnace atmosphere. 
The problem of trace impurities is exacerbated as the temperature increases. Depending on the process and material, even small variations in the temperature or impurity level can shift a reducing or neutral atmosphere to an oxidizing one, with a negative impact on the quality of the treated parts. 
To counteract the temperature effect, reactive species (H2 and CxHy) can be added to scavenge impurities and maintain the required potential for the material being processed. Control systems have gained increasing acceptance to regulate the amount of reactive species added. However, ensuring proper control is not simply a matter of installing elaborate equipment; it also requires accurate knowledge of which variables must be controlled and how close the control must be in any given case.


In the sintering furnace, continuous measurement and control of furnace atmosphere is increasingly important to improve quality control, reduce costs, and comply with regulatory requirements. To continuously measure dew point and hydrogen concentration together gives the furnace operator the ability to know more accurately the furnace atmosphere composition and flow pattern. Air Products has developed a novel gas density sensor and successfully implemented it for hydrogen concentration measurement of hot zone nitrogen-hydrogen atmosphere.