Trace Oxygen measuring systems for Reflow and Wave solder machines

Most manufacturers and users of inerted reflow and wave soldering ovens use trace O2 analysers 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. We are the only company that has the option of RACE™ technology. This technology employs a second fuel cell which protects the first cell from being exposed to high concentrations of O2. The guarded cell never sees high O2levels and therefore responds very quickly, just as quickly as a Zirconia based system at the normal O2 levels seen by soldering ovens. Systech Illinois have Patents on this technology and therefore it is not available from any other manufacturer. Systech Illinois have the fastest solution available in the marketplace. With our RACE™ technology there is no need to use a special filter canister to absorb the volatiles/hydrocarbons. This gives far better response times and much lower running costs. Filters do not have to be replaced therefore operators do not have to remember this task, providing continuous accurate measurement. Zirconia Based instruments 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%. Advantages: The response time is very fast, and much faster than the Fuel Cell approach. There is usually no problem with the speed of measurement. The sensor is non- depleting; in other words it will last the lifetime of the instrument. Disadvantages: In the presence of hydrocarbons the oxygen that the instrument is trying to measure is catalytically converted to CO2 or other elements and therefore measures oxygen concentrations much lower than expected. In order to overcome this manufacturers use a special filter canister to absorb these volatiles/hydrocarbons. This increases the time response and running costs and inevitably because the filter has to be replaced often, operators do not carry out these tasks, with breakdown of the measurement. Some manufacturers have what claim to be non-catalytic sensors, which do not work effectively in such high hydrocarbon conditions that exist. Fuel Cell based instruments 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. T

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