Most manufacturers and users of inerted reflow and wave soldering ovens use trace O2 analyzers to either measure the oxygen impurity or even with a feedback loop control the O2 impurity.
There are many manufacturers of these instruments but only a small number that operate on a worldwide basis, with corporate service centres and knowledgeable representatives.
There are two major technologies used in these types of applications, namely Zirconia, ceramic, solid state and Fuel Cell. There are advantages and disadvantages with both of these types.
Many manufacturers only produce one of these types.
Systech Illinois (formerly Systech Instruments Ltd and Illinois Instruments Inc.) manufacture both types and with over 22 years of experience have sold more than seven hundred solutions. Ever since the pioneers of Soldering ovens began introducing Nitrogen into the controlled atmosphere to improve the production quality of circuit boards.
Here at Systech Illinois, we believe that we have the best solutions available in both Cell types and technologies. We are the best in the market today because we have an additional solution that no one else has…the RACE™ Cell.
How does it work?
The instrument utilises a Zirconia cell to detect oxygen concentrations. The Zirconia cell is an electrochemical galvanic cell employing a high temperature ceramic sensor containing stabilised zirconium oxide.
The instrument is a self contained unit with the Zirconia cell mounted in a high temperature controlled furnace. The necessary electronics process the signal from the detection cell and display it directly via a digital display as oxygen concentration over the range 0.01vpm to 100%.
How does it work?
The cell performs essentially as a battery and consists of two electrodes in contact with a liquid or semi-solid electrolyte. The electrodes are connected through an external electronic metering circuit. Oxygen comes in contact with the negatively charged cathode (usually silver) where the first of two reactions take place. Oxygen is reduced (electron consumption) to the negatively charged hydroxyl species anode (usually lead) where the second reaction takes place. The hydroxyl ions react with the lead which is subsequently oxidised (release of electrons) to lead oxide. The use (reduction) and release (oxidation) of electrons results in a flow of electrons proportional to the oxygen concentration and is measured by the generation of an electric current.
Systech Illinois is completely independent on this issue! We make both types and we have no preference.
Some manufacturers have to use Zirconia because the Fuel Cell is too slow. However Zirconia needs the use of expensive filters that normally do not get replaced, rendering the installation useless.
We find that most of our customers use our RACE™ Fuel cell based system, but not all. We have no preference and can advise the prospective customer of the best solution for their application site.
9500/8500 Oxygen Control System
The Zirconia or Fuel cell technology instruments are available as fully controlled Oxygen measuring and feedback control instruments.
The instrument not only measures and displays the Oxygen concentration, by employing a fuzzy logic control algorithm and control valve on the incoming Nitrogen feed to the oven but it can also control the O2 impurity.
We are finding more and more of our sales to these applications are control systems.