Invacare IRC5P - SensO2 Oxygen Sensor Technology; Operating Sequence

SECTION 2—INSTALLATION/SEQUENCE OF OPERATION
Part No 1148070 13 Perfecto
2
™
Theelectricalactivationofthe4‐wayValveisaccomplishedevery8to15secondsbythe
pressuresensorandP.C.Boardelectronicswhenthepressurereachesasetpointof21
p.s.i.(144.79kPa)outputflows4L/minandaboveor16p.s.i.(110.32kPa)outputflows3
L/minandbelow.Thetimebetweencyclesisdependentonaltitude,flowrateand
internalenvironmentalfactors.
AP.E.valveopensjustpriortotheshiftofthe4‐wayvalve.Thisallowshighly
concentratedoxygentoenterthejustexhaustedbedfromthetop.Thisadditional
pressureallowsthebedtostartitscycleatahigherpressure.TheP.E . valvewillclosejust
aftertheshiftofthe4‐wayvalve.
Ifmainpowerislost,theBatteryFreePowerLossAlarmwillsoundashortʺBEEPʺ,with
alongpauseafter.Allunitsareequippedwithadiagnosticalarmsystemthatsignalsif
thepneumaticpressureorelectricalsystemsmalfunction.Thetroubleshootingguidein
thismanualexplainsthealarmsystemsignalsandreasons,indetail.Referto
Troubleshooting
onpage 16.
SensO
2
Oxygen Sensor Technology - Ceramic Zirconia
Sensor
Technical Description
Theoxygenbeingproducedbytheconcentratorflowsoutoftheproducttankandinto
theflowmeter.Asmallflowofoxygenproducedbytheunitissentthroughaprecision
orificetotheoxygensensormountedontheprintedcircuitboard.
Astheoxygenentersthesensor,itpassesthroughascreenandcontactsthesensingdisk.
Electriccurrentflowingthroughametalfilmresistorheatsthediskinexcessof300°

C.
Oxygenmoleculescontacttheelectrodeofthediskandpick‐upextraelectronstobecome
oxygenions.Theseoxygenionsareattractedtotheelectrodeonthebottomofthezirconia
sensingdisk.Becauseofthecrystalstructureofthezirconia,onlyoxygenionscanpass
through.Whentheoxygen
ionsreachthebottomelectrode,theextraelectronsare
releasedfromtheoxygenionsandoxygenmoleculesreturntotheair.Thenumberof
electronsisdirectlyrelatedtotheoxygenconcentration.TheelectronstraveltotheP.C.
boardwheretheyarecountedandtheoxygenconcentrationreadingiscalculated.
A
microprocessorontheP.C.boardcontainssoftwarethatinterpretsthesignalbeing
receivedfromthesensor.Itcomparesthesignaltoclinicallyacceptablelimits.Signals
outsideoftheclinicallyacceptablelimitsgenerateresponsesintheformoflights,audible
indicators,and/orsystemshut‐down.
Operating Sequence
Oncethepowerswitchhasbeenturnedon( ),theSensO
2
circuitwillwaitfiveminutes
fortheconcentratortobeginproducingclinicallyacceptableoxygenandtheoxygen
sensortostabilize.TheGREENlightwillilluminate(indicatingnormalsystemoperation)
whiletheoxygensensoriswarmingup.
I/