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FEATURES AND BENEFITS OF THE SERIES 1000 OXYGEN MONITOR

FEATURESFull three-year sensor warranty.Exceptional speed of response.Patented extended life oxygen sensor.Economically priced.WATCHMAN CIRCUIT™CO BENEFITS Ensures trouble-free and cost-effective operation when compared to sensors having 6-12 month warranties. Detects oxygen alarm events in seconds . Eliminates frequent sensor replacement and annoying false low-oxygen alarms .Maintenance costs are significantly reduced. Saves hundreds of dollars per point. Alerts users of major status changes in the Series 1000 Oxygen Monitor and the environment.
2 resistant sensor.Optional RS-232C or RS-485 outputs.Open sensor diffuser. Eliminates sample conditioning and premature sensor failures,while minimizing routine maintenance.Control several monitors on one communicationschannel along with security code protection. No dependence on a sample pump or aspirator. HISTORICAL PERSPECTIVE The majority of oxygen monitors use disposable galvanic (electro-chemical) sensors that consist of either a gold or silver cathode,lead anode,and potassium hydroxide (KOH) electrolyte.The sen-sors use the linear relationship between the oxygen concentra-tion in the sample gas and the electron (current) flow betweenthe cathode and anode produced from the following reactions:O Disposable Potassium Hydroxide-Based Sensors
3 ).The adverse effect from the formation of lead car-bonate is similar to that produced by PbO,i.e.,a reduction in theoutput of the sensor followed by its demise.The higher the con-centration of CO
2 ,the sooner problems arise with the sensor.Relatively low concentrations of CO
2 in ambient air (400-1,000ppm) produce adverse effects unless provisions are made to scrubthe CO prior to analysis.Disposable KOH-based oxygen sensors have earned a dubiousreputation for performance,and rightfully so.Upon start-up thesensors work well,but shortly thereafter,difficulties begin to arise.Because of this fact,many manufacturers limit their sensor warranty to 6-12 months .Over the first three years of opera-tion,it is not uncommon to find users paying actual low-oxygen alarm condi-tion takes place and the warning is not heeded,the safety ofemployees could be severely jeopardized.
2 $1,300-$1,800 each ,so warrantyreplacement,after only 24 months,can cost as much as two times the initial cost of the instrument read the fineprint frequent false low-oxygen alarms .False low-oxygen alarmsinvariably lead to the "cry wolf" syndrome,where personnelassume the alarms are produced from a faulty oxygen sensor.Under these conditions,if an There are manufacturers who claim their oxygen sensors will lastthe life of the instrument.To differentiate their sensors from thedisposable types,they offer extended sensor warranties.At first,these warranties may seem quite attractive,but .The sensor warranty is usually in replacement sensors. prorated .After the first 12months of usage,the customer is "on-the-hook" for an increasing-ly larger portion of the warranty replacement cost.Prices for thesensors range between $700.00 . Acid Gas Poisoning
2 + 2H
2 O + 4e- 4OH- (cathode reaction)2Pb + 4OH- Also shortening the life of the disposable KOH-based sensor is itssusceptibility to carbon dioxide (CO Beware of Prorated Warranties! 2PbO + 2H
2 O + 4e-(anode reaction) Major Limitation The reaction at the anode produces lead oxide (PbO),a compoundwith a low solubility limit in potassium hydroxide electrolyte.After a sensor has been exposed to oxygen for a period of time,the electrolyte loses its ability to maintain the lead oxide in solu-tion.As more lead oxide is formed,it begins to deposit (passi-vate) on the anode.As passivation progresses,the linear relation-ship described above becomes distorted,causing a reduction inthe output of the sensor,and eventual sensor failure.A major dif-ficulty resulting from the drop in sensor output is the occurrenceof

ALPHAOMEGAINSTRUMENTSHAS ABETTER SOLUTION.

2 ) poisoning.CO
2 in the sample gas dissolves in the KOH electrolyte,forming lead carbon-ate (PbCO