The AutoBlend gas standards generator provides:

  • Six independent permeation tube ovens with wide temperature range controlled to 0.1 °C
  • Primary dilution mass flow rate to 10 l/min
  • Secondary dilution mass flow rate to 10 l/min
  • Can create mixtures with up to 48 permeation tube components
  • Dual headspace and humidification options available

The AutoBlend is an integrated computer-controlled gas blending system designed to create flowing, adjustable-concentration complex gas mixtures and test atmospheres. The system introduces precisely controlled trace concentration components into a flowing, high purity matrix gas.

 

Special AutoBlend software

 

The AutoBlend uses KIN-TEK Trace Source disposablerefillable and diffusion permeation tubes for over 500 chemicals
The AutoBlend has six permeation tube ovens. Each oven can generate its component concentrations independent of the other ovens.  This is an extremely powerful feature for dynamically testing the effects of a wide range of vapor contaminants since each oven can be switched in (span) and out (vent), and the concentrations generated by each spanning oven are independent of the concentrations generated by the other spanning ovens.

The base gas mixture created in each oven can contain up to eight different analyte components so that a test atmosphere can be spiked with up to 48 components simultaneously.
A small flow of pure dilution gas passes over the permeation (or diffusion) tubes installed in each oven to form a base gas mixture.  A variable portion of each base gas mixture is then added to a main dilution flow to create a primary mixture with variable concentration ratios. 
A secondary dilution feature provides a large dynamic concentration range.  Secondary dilution is used or bypassed automatically in the system as required to produce target concentrations.
In many applications normally innocuous contaminants that occur routinely, or randomly, may be significant for testing purposes.  In the AutoBlend™, two optional dynamic headspace saturation modules can be added (as shown in bottom cabinet above) to allow the addition of vapors from potential transient interfering compounds such as cleaning solutions, fuels or paints.  Output from the headspace modules can be added either before or after secondary dilution of the trace components.
The resulting test atmosphere can be supplied either dry or at variable humidity levels with the optional humidification module.  Humidity is added by splitting the total dilution flow into two parts.  One part remains dry and contains all of the trace components from the permeation tubes and headspace modules.  The other portion of the dilution gas is saturated with water vapor.  The two portions are combined at the output of the system to form the humidified mixture.  Relative humidity (RH) is varied by varying the ratio of humidified diluent to dry diluent. The trace components do not contact liquid water in the system.
Hardware is included to assure constant gas stream output conditions independent of variations in flow and pressure. This is particulary important for applications where flow capacity is limited (e.g., filling of gas bags), or when back pressure is required to introduce the output gas stream sample to the device under test at an elevated pressure. Controls are provided on the front panel for adjusting the output pressure. 

Typical AutoBlend applications include:

  • Sensor response evaluation to various combination of gases
  • Catalyst research
  • Inhalation toxicology
  • Fuel cell development
  • Analytical methods development
  • Chemical effects testing
  • Creating complex test atmospheres.

Evaluating Sensor Response

Chemical sensor systems are typically designed to give rapid indication of the concentration or change of a hazardous substance in a normally safe background.  Often, however, many innocuous and possibly interfering compounds are also routinely or transiently present.  For example, DEET-based mosquito repellant commonly used in an outdoor location might result in false positive toxic gas alarms. Or the presence of a safe compound might suppress response to a hazardous compound. Often, sensors either respond to atmospheric humidity, or their response is affected by humidity.  Identifying and quantifying such interactions is critical to qualifying a sensor system for use in a specific application.

Catalyst Research

In catalyst research and development it is important to define and quantify the effects of reactant impurities and combinations of impurities on yield and catalyst life.  The AutoBlend system’s ability to vary relative concentrations of the components can dramatically reduce testing time. It facilitates discovery of synergistic effects and is ideal for executing statistically designed vapor testing programs.

Inhalation Toxicology

The AutoBlend, with its capability to give varying ratios between components, coupled with its integral variable humidity source and the adjustable headspace vapor modules, is an extremely versatile source of test atmosphere for inhalation toxicology studies.  The system is simple to set up for a wide range compounds.  It can give concentrations from hundreds of ppm down to low ppb, and mix them into humidified air also containing various common and normally innocuous atmospheric contaminants.

Fuel Cell Development

Fuel cells offer an opportunity for direct, or near direct conversion of chemical compounds to electrical energy with minimal environmental pollution.  Success of these efforts requires development of robust catalytic systems, and thus an intimate knowledge of the long-term effects of various fuel and air (or other oxidant) contaminants.  The AutoBlend system is an excellent source for long term testing of fuel cell systems known concentration conditions.

Validating Analytical Methods

Effective analytical methods must work equally well in any laboratory setting and with a wide range of variation of reagent and/or matrix composition.  The flexibility of the AutoBlend system allows for rapid and thorough evaluation analytical methods.  A clear understanding of the method and significant parameters is essential to establishing standard methods.

Chemical Effects Testing

A chemical environment can have varying effects on a device under test based on interaction among the chemicals as well as the device. With the six independent permeation tube ovens of the AutoBlend (and up to 8 chemicals per oven), plus the optional dual headspace and humidification capabilities, a complex method can be setup in which some component concentrations are generated for the current test point, followed by different sets of chemical concentrations in the following test points. Each point of the method allows for a "run time" before automatically advancing to the next point. "Zero" points can be inserted to clear the test atmosphere at appropriate times.

Creating Complex Test Atmospheres

All of the above applications are examples of creating complex test atmospheres.