Finite - Team Technical

1 The Basics of CoalescingCompressed Air & Gas FiltrationBulletin 1300 - 700/USAF inite For more information regarding coalescing filtration, please call Finite at 1-800-521-4357 Finite The Basics of Coalescingis intended to familiarize theuser with all aspects ofcoalescing filtration from thebasics to advanced is dedicated as a referencesource with the intent of clearlyand completely presenting thesubject matter to the user,regardless of the individual levelof selection and proper use offiltration devices is an importanttool in the battle to decreaseproduction handbook will help the usermake informed decisions aboutcoalescing IS COALESCING FILTRATION?4 WHY FILT E R COMPRESSED AIR?5 THE COMPRESSED AIR ENVIRONMENT6 SUBMICRONIC CONTAMINATION7 THREE CONTAMINATION THREATS8-9 COALESCING MECHANISMS10-11 COALESCING FILT E R DESIGN12 FILT E R EFFICIENCY13 Finite MEDIA GRADES14-15 Finite MEDIA TYPES16 FILT E R SELECTION17 FILT E R HOUSINGS18 FILT E R INSTALLATION19 MAINTENANCE20 FILT E R ELEMENT LIFE PROFILE21 COALESCING FILT E R LOADING CURVE22 THE DIRECT COST OF PRESSURE DROP23 APPLICATIONS24-27table of steady state process whereby aerosols are caused toagglomerate (come together) into even larger droplets as theypass through the filter element s fiber matrix, eventually becominglarge enough to be gravitationally drained InAir OutThis filter housing cutawaydepicts the coalescingprocess.

2 Air enters thehousing and flows throughthe filter media passing fromthe inside element surface tothe outside. Coalesced liquidcollects in the bowl where itis drained and clean airexits the housing throughthe outlet \ko- -les\ ; ;1. to grow together 2. to unite as a whole3. to unite for a common end: join \fil-tra-sh n\1. the process of filtering 2. the process of passingthrough or as if through a filter isa dictionar y definition4 Parker Hannifin CorporationFiltration and Separation DivisionOxford, MILook for these excitingfiltration facts through-out the air?factStandard nominal five micron inline filters cannot removesubmicronic contaminants as required in criticalapplications. The lowest particle removal limit for thesegeneral purpose filters is 2 m. Eighty percent of aerosolcontaminants are under 2 m in size. Coalescing filters,however, are specifically designed to remove submicronicoil, water and solid contamination from compressed graded-porosity coalescing filters remove of all aerosols in the to m range.

3 Inaddition, these filters are over effective atremoving all aerosols and solid particles larger than , oil aerosols at a 20 ppm contamination level arereduced to a ppm concentration acceptable forvirtually all pneumatic filters are specificallydesigned to remove submicroniccontamination from compressed airSubmicronic contaminants incompressed air systemsplug orifices of sensitivepneumatic instrumentation; theywear out seals, erode systemcomponents, reduce theabsorptive capacity of desiccantair/gas dehydrators, foul heattransfer surfaces, reduce air toolefficiency, and damage finishedproducts. The results include:product rejects, lost productiontime and increased maintenanceexpense. For example, traceamounts of submicronic oil cancause serious fish eye blemishingin automotive finishing left in air lines can freezeduring exposure to cold, blockingflow or rupturing pipes. Compres-sor lubricant not captured in acoalescing filter will eventuallycollect in pneumatic components,causing premature componentrepair or replacement.

4 Environ-mental concerns will be raised ifoily, compressed air is continuallydischarged into the atmospherethrough a pneumatic materials, provideand control energy andprotect equipment orpersonnel. Clean air in theseand other criticalapplications must be free ofboth solid particulatecontamination and liquidABDFGEC other typicalapplications: Pneumatic conveyors Beverage dispensers Spray paint equipment Gas separator systems Pneumatic power systems Air logic and control circuits Laboratory and process gas usage Air gauging in manufacturingprocesses Breathing air(fixed or portable systems) Cooling and protecting sensitiveinstruments Air bearings for mechanicalpower transmission Aeration in pharmaceuticaland chemical processescoalescing filters provide clean air for a variety of applicationsaerosols. These oil andwater aerosols are beyondthe control of conventionalfilter systems and can onlybe removed with compressed air environment6 ACompressor Room/ControlsBMedical/DentalCFood Packaging/Beverage BottlingDMicroelectronicsEPlastic Blow MoldingFSpray Painting/Powder CoatingG Packaging/PrintingClean compressed air isessential in suchindustries as foodprocessing, electronics,health care, photography,dairy and air and othergases are widely used toParker Hannifin CorporationFiltration and Separation DivisionOxford, MIThe symbol for amicron is: mCompressed air is so widelyused it is often called s fourth you know that amicron is also knownas a micrometer, whichis one millionth of ameter?

5 FactMost process and lab gas applicationsrequire a high degree ofpurity. Most compressed airapplications also workbetter if the air is clean anddry. The four classes ofcontaminants incompressed air are water,oil, solid (particulate) andunwanted gases. Typicallythe first three are in theform of aerosols. An aerosolis a suspension of smallsolid or liquid particles in agas. Typically, the particlesare between and 10microns in diameter. Amicron, identified by thesymbol m and alsoknown as a micrometer, isone millionth of a meter (orabout inches) insize. A typical strand ofhuman hair is approximately80 microns in diameter,while a grain of table salt isapproximately 100 micronsin size. The lower level ofvisibility to the human eye is40 regulations statethat air may not containmore than five milligrams(mg.) of oil mist particlesper cubic meter of plant air,or one ounce of oil in200,000 cubic feet yetanother reason why cleancompressed air is a concernin industrial contamination isparticularly threatening inprecision applications wherethe cleanliness of theworkplace and the purity ofthe product are critical.

6 Inclose-tolerance systemswhere extremely fineorifices and partsclearances are the norm, itis vital for the system air tobe free of all suspendedliquid aerosols as well Sizes of ParticlesSubstanceMicronsInchesGrain of table salt Hair limit of visibility Flour 25 .0010 Red Blood Cells contaminationwhy submicronic contamination is a problemwater, oil and solids are three contaminant threatswater vaporswater emulsionscondensed moistureoil vaporspaint vaporsvolatile solvent vaporscompressor lube oilscondensed oilscarbonized oils (varnish)solutions of dissimilar oilsmixes of all the abovePossible Contaminants:waterthree contaminationOil is alsopresent islargelyintroducedinto the airstream by theair compressor. The amountof oil introduced in thisfashion varies by the typeof compressor of thehydrocarbon content ofdischarge air from typicalcompressors are expressedin parts per million (ppm):contains 20-30 ppm ofhydrocarbon aerosolsfrom industrial andautomotive compressorscan condenseapproximately 10 ppmof hydrocarbons duringthe compression is enough oil togum-up air linecomponents and tocollect in air dryersystems.

7 A majority ofthe oil aerosolsemitted by aircompressors are 2 mand Screw 25 to 75 ppm at 200 F. Reciprocating 5 to 50 ppm at 350 F. Centrifugal 5 to 15 ppm at 300 a concentration of 25ppm, a typicalcompressor flowing 100 SCFM for 35 hours willintroduce eight ouncesof oil into the if an oil-lesscompressor is used, oilcontamination of the airstream remains a problembecause ambient air18 gallons of water aerosols incompressed air range to 10 m. While airdryer systems can beThe contaminants ofgreatest concern inprecision compressed airsystems are water, oil andsolids. Water vapor ispresent in all compressedair; it becomes greatlyconcentrated by thecompression process. Infact, compressed air issaturated with water untilit is dried. A 25 hpcompressor delivering100 standard cubic feetof air per minute (SCFM)at 100 PSIG can produceused effectively toremove water fromcompressed air, theywill not remove thesecond major liquidcontaminant Contaminants:Parker Hannifin CorporationFiltration and Separation DivisionOxford, MI8 The third contaminant found incompressed air is solid matterincluding rust and scale.

8 Solidparticulates, combined withaerosol water and oil, can clogand shorten the life of airsystem components as well asfilter systems. Most rust andscale contaminants typicallyfound in compressed airsystems are to 5 m pictomicroraph of particulate contaminants(Magnified 100x Scale: 1 division = 20 microns)pipe scale / rustrockspollenyeast cellsairborne carbonmoldwelding flashpenicillinPossible Contaminants:25solidOil and water contamination increase silting123456789012341234567890123412345 6789012341234567890123412345678901234123 4567890123412345678901234123456789012341 2345678901234123456789012341234567890123 4512345678901234512345678901234512345678 9012345123456789012345123456789012345123 4567890123451234567890123451234567890123 4512345678901234512345678901234567890123 4567890121234512345678901234567890123456 7890121234512345678901234567890123456789 0121234512345678901234567890123456789012 1234512345678901234567890123456789012123 4512345678901234567890123456789012123451 2345678901234567890123456789012123451234 5678901234567890123456789012123451234567 890123456789012345678901212345 Submicronic particle buildup can interferewith movement and cause wearn threatscoalescing mechanSeparation of aerosol andsolid contaminants from airis primarily dictated bygravity.

9 Contaminantsgreater than 10 m in sizesettle out of the air streamfairly quickly. However,extremely small aerosolparticles remain suspended,particularly in flowing asopposed to still air. Mostcoalescing filters aredesigned to causecombining of smalleraerosols into larger enlarged droplets arenow susceptible to theeffects of gravity. Coalescing is the termgiven to this coalescing processcan be visualized as theatmospheric conditions atwork in a thunderstorm many small water vapormolecules present inturbulent moisture-laden aircondense into aerosolswhich then collide or cometogether to formincreasingly larger dropletmasses until they gainenough weight to react togravity and fall to earth filterseliminate submicroniccontamination through threeconcurrent processes,depending on aerosol : Aerosols .001to .2 Interception: Aerosols .2to 2 Direct Impact: Aerosolsover 2 mechanisms of the coalescing processDid you know that in1994 Finite Filterjoined -Compressed Air andGas Institute, anorganization commit-ted to the develop-ment of the indus-try?

10 FactAerosols and solids in to m range are subject torapid random Brownian motion,moving completely independently ofthe bulk air stream as extremelysmall aerosols in flowing air. Thismotion causes them to migrate fromthe air stream and to collide withexposed filter surfaces. Solidcontaminants adhere permanently tothese surfaces via intermolecularforces. Liquid droplets, however,migrate gravitationally down the filterfibers, joining other droplets to formlarger masses of liquid which can bedrained from the system. While therate of diffusion activity increases withheightened temperature and pressure,contaminants of this size exhibitrandom motion and are subject todiffusion coalescing even under non-turbulent, low velocity flow to .2 mBROWNIAN MOTION PATH10 Parker Hannifin CorporationFiltration and Separation DivisionOxford, to 2 mAEROSOLS FOLLOWSLIP-STREAMFor contaminants to 2 m in size,interception is the predominantcoalescing mechanism.