Gas analyzers and sensors with detection limits at parts-per-million (PPM) and billion (PPB) concentrations require precise calibration to ensure reliable measurements. Low-concentration mixtures are preferable for this task. They not only prioritize safety—particularly with flammable or toxic gases—but also mimic real-world scenarios. However, pre-mixed gas cylinders fall short of creating stable, low-concentration mixtures due to their sensitivity to slight changes in gas levels and potential reactions with cylinder walls. 

Gas permeation ovens are the superior solution for generating affordable, reliable, ultra-low-concentration mixtures. By controlling flow rate, pressure, and temperature, permeation ovens deliver unparalleled accuracy and consistency. Join us as we explore permeation ovens’ game-changing potential in creating extremely low-concentration mixtures.

Mechanism of Gas Permeation Ovens

A gas permeation oven operates by utilizing permeation tubes filled with a liquid compound of the desired gas. The permeation tubes are disposable and designed to facilitate the permeation of the liquid through their walls when heated. The oven heats these tubes, causing the liquid to vaporize and permeate through the tube walls at a controlled rate. This vapor then mixes with a controlled flow of carrier gas passing through the oven. As a result, a precise low concentration mixture is formed.

The process involves several critical components:

  1. Permeation Tubes: These are specialized tubes containing the liquid compound. The tube material and construction ensure a steady permeation rate when heated.
  2. Temperature Control: Precise temperature control is vital, as the permeation rate is highly sensitive to temperature variations. Modern permeation ovens can maintain temperature stability within ±0.1°C, ensuring consistent gas generation.
  3. Gas Flow: The carrier gas flow rate is controlled by mass flow controllers. These are integrated into the oven system to ensure a stable and accurate flow of gas.

Advantages of Gas Permeation Ovens

Gas permeation ovens offer several key advantages over traditional methods of generating low concentration gas mixtures:

  1. Ultra-Low Concentrations: Permeation ovens can generate extremely low concentrations, even sub-ppb levels. This capability is challenging to achieve with premixed gas cylinders due to adsorption effects. Here gasses adhere to the cylinder walls, altering the concentration over time.
  2. On-Demand Fresh Mixtures: The ability to generate fresh mixtures on-demand ensures accuracy. It also avoids the issue of cylinder concentrations changing over time because of gas adsorption or degradation.
  3. Cost-Effectiveness and Convenience: A permeation oven has a compact size and uses disposable permeation tubes. Therefore, it can offer easy operation and maintenance. This setup is more cost-effective compared to maintaining and replacing gas cylinders.
  4. Precision and Stability: With precise temperature control, permeation ovens provide stable and reliable gas mixtures. The tight regulation of the permeation rate ensures consistent output, which is crucial for applications requiring high accuracy.

Applications of Gas Permeation Ovens

Gas permeation ovens are versatile tools with applications across various industries:

  1. Analytical Instrument Calibration: Gas permeation ovens are widely used for calibrating analytical instruments, such as gas chromatographs and mass spectrometers. Accurate calibration ensures the reliability and accuracy of these instruments, which are essential for quality control and research.
  2. Test Atmospheres: In environmental monitoring and research, creating controlled test atmospheres with specific gas concentrations is necessary. Permeation ovens provide the precision needed for such applications, allowing for the study of pollutant effects and atmospheric chemistry.
  3. Specialized Gas Blending: Industries like chemical processing and pharmaceuticals often require specific gas blends for various processes. Permeation ovens can house multiple permeation tubes simultaneously. This can enable the creation of multi-component gas mixtures tailored to specific needs.
  4. Environmental Monitoring: Accurate low concentration gas mixtures are critical for monitoring air quality and detecting trace pollutants. Permeation ovens support the generation of standard gasses required for calibrating air quality monitoring equipment.

Gas permeation ovens represent a sophisticated solution for generating extremely low concentration gas mixtures with high precision and reliability. They are indispensable for a variety of applications because they can produce sub-ppb gas levels, combined with:

  • On-demand generation
  • Cost-effectiveness
  • Precise control.

From calibrating analytical instruments to creating controlled test atmospheres, permeation ovens are vital tools in advancing environmental monitoring, chemical processing, and beyond.

Enhance The Reliability of Your Gas Mixtures With Equipment From Environics

A refined gas mixture is crucial for ensuring the equipment utilized for analysis, such as gas detectors, is well-calibrated and, thus, can produce accurate results. If you are searching for equipment that can help you create specific gas mixtures, look no further than the instruments listed on Environics. We have a number of permeation systems available for you to choose from. This includes the Series 500 Stand Alone Permeation System, a permeation device which incorporates an oven utilizing both multiple and singular permeation tubing. It is stable and dependable and can be applied in temperatures reaching 100°C. Alongside this equipment, we can add customizable permeation devices to gas mixers and blenders, such as our Series 4000 which can allow additional dilution of the oven output or mixing with additional gases.

With so many instruments available for creating gas mixtures, there is no doubt that you will find the perfect device for your intended application. Speak with our specialists and locate a permeation system to help you achieve a gas mixture that can be trusted.