Dew Point & Compressed Air - ROTRONIC...• High cost in purge air is reduced • Some HDD consume...
Transcript of Dew Point & Compressed Air - ROTRONIC...• High cost in purge air is reduced • Some HDD consume...
DewPoint&CompressedAir
Helping you make a better measurement.
BruceMcDuffee MichaelBoetzkes
WebinarPresenters&HumidityExperts
Agenda&TakeawaysAgenda• DefinitionofDewPoint• PressureEffect• ISOAirClasses&Dryers• DesiccantDryersandEfficiency• WaterinAir– practicalexample• Summary
Takeaways• Understandingtheparameterhelpstomakeabettermeasurementandpreventwater.
• Learnthecauseofliquidwaterinthesystem.
• Understandhowpressureaffectsthemeasurement.
• Understanddryerperformanceanddewpoint.
DefinitionofDewPointTemperature
• Dewpointtemperatureisthetemperatureatwhichwatervaporwillbegintocondense.
• Thetemperatureatwhichamoistgasissaturatedoveraplanesurfaceofpureliquidwater.
Note– Dewpointtemperaturedoesnotchangeastemperaturechanges.
WhataboutFrostPoint?
• Thetemperatureatwhichamoistgasissaturatedoveraplanesurfaceofpureice.
• Whichoneareyoumeasuring?• Whichonemattersincompressedair?
Note– Dewpointislowerthanfrostpoint (byabout4Cat-40).
WhyIsDewPointTemperaturesoImportant?
• Waterincompressedaircausesproblems.
• IfDp reachesambienttemperature,condensationoccurs.
• Dewpointtemperaturechangeswithpressureandwithdryerperformance.
PressureEffectsonDewPoint
Ruleofthumb:• Aspressureincreases,dewpointtemperaturerisesandapproachessaturation.
• Aspressuredecreases,dewpointtemperaturegoeslowerandtheairbecomesdryer(relativelyspeaking)
PressureDewPointvs AtmosphericDewPoint
• PressureDewPointisthedewpointattheactualpressure.
• AtmosphericDewPointiswhatthatdewpointwouldbeiftheairwereexpandedtoatm pressureor0psig.
• Knowwhatyourhygrometerisreporting– pressureDp orAtm Dp.
Comments&Questions
Ifwedon’tgettoyourquestion today,we’llrespondviaemailafterthewebinar.
WhereShouldyouMeasureDewPoint?
AirClassification- ISO8573.1(pressuredewpointonly)Class Particles
max inmicronsDewPoint C DewPointF Oil
mg/m3
1 0.1 -70 -94 0.012 1 -40 -40 0.13 5 -20 -4 14 15 3 38 55 40 7 45 >56 - 10 50 -
HeatlessDesiccantDryersDewPoint
DewpointDemandSwitching• Heatlessregenerativedryers• Highcostinpurgeairisreduced• SomeHDDconsumeupto15%oftheirratedcapacityinpurgeairwithoutDDS.
For example:• If a dryer is rated for -40 Dp at 1000 cfm, it requires
150cfm just for purge air.• This is equal to a 35HP compressor running 24/7 just to
purge the dryer.
PracticalExamples
1. Dewpoint=38F;airlinegoesoutsidein30F;frozenwater
2. Dewpointinstrumentreads-20FDp;whatistruepressureDp?
3. PressureDp=+38Fat70psig;atmDp =-2F• Increasepressureto150psig;PressureDp=+55F
Comments&Questions
Ifwedon’tgettoyourquestion today,we’llrespondviaemailafterthewebinar.
NextWebinarsProductWebinar– RotronicWirelessDataLoggerTuesday,March22nd1:00PMEDTRegisteratwww.rotronic-usa.com/product-webinars
ProductWebinar– LowDewPointProbeTuesday,April5, 1:00PMEDTRegisteratwww.rotronic-usa.com/product-webinars
Helpingyoumakeabetterhumiditymeasurement– andmore.
Transmitters,portablemetersandloggersfor:
• Humidity• CarbonDioxide• LowDewPoint• WaterActivity• DifferentialPressure• MonitoringsystemsforcGMP• ISO17025calibrations(humidityandtemperature)
Postwebinarsurvey
Thankyou!email:[email protected]:www.rotronic-usa.comCanada:www.rotronic.caOutsideAmericas:www.rotronic.com
Futurewebinarregistrations:www.rotronic-usa.com/humidity-webinars
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