Air Cooled Service Basics 1

8/12/2019 Air Cooled Service Basics 1

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Air Cooled Heat Exchanger BasicsAir Cooled Heat Exchanger Basics

This session will cover the following:This session will cover the following: Types of CoolersTypes of Coolers

Standard ConstructionStandard Construction

FansFans

InstallationInstallation

StartStart--upup Routine ServiceRoutine Service


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ACE ModelsACE Models

Model CModel C --

Vertical coilsVertical coils

Induced or forcedInduced or forceddraft fandraft fan

Horizontal air inlet,Horizontal air inlet,horizontal air outlethorizontal air outlet


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Model EModel E

Horizontal CoilHorizontal Coil

Forced draftForced draft

Can have multipleCan have multiplefansfans

Vertical air inlet,Vertical air inlet,

vertical air outletvertical air outlet


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Model JModel J

Vertical coilsVertical coils

Induced draft fanInduced draft fan

Horizontal air inlet,Horizontal air inlet,vertical air outletvertical air outlet


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Model AModel A

Slanted CoilSlanted Coil

Forced draft fanForced draft fan

Horizontal air inlet,Horizontal air inlet,vertical air outletvertical air outlet


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Model TModel T

Horizontal coilsHorizontal coils

Forced draftForced draft Can have multipleCan have multiple

fansfans

Horizontal air inlet,Horizontal air inlet,

vertical air outletvertical air outlet


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HeadersHeadersNormally built to ASME codeNormally built to ASME code

Box TypeBox Type

Gas headers are fabricated from plate. All areGas headers are fabricated from plate. All areASME stamped.ASME stamped.

Water sections are usually rectangular tubing.Water sections are usually rectangular tubing.

Not normally code stampedNot normally code stamped


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HeadersHeadersFloating header onFloating header on

one endone end

Fixed on the otherFixed on the other


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TubesTubes Finned with marine grade aluminumFinned with marine grade aluminum

LL--footed, normally slotted to enhance heatfooted, normally slotted to enhance heattransfer to airtransfer to air

Tension wrapped and stapledTension wrapped and stapled

Expanded into tube sheets using a rollerExpanded into tube sheets using a roller

May be grooved for some servicesMay be grooved for some services


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StructureStructure Fabricated from structural steel, primed andFabricated from structural steel, primed and

painted prior to assembly, then touched uppainted prior to assembly, then touched up prioorprioorto shipmentto shipment

May be galvanized or metalized instead ofMay be galvanized or metalized instead ofpainted prior to assemblypainted prior to assembly

Sheet metal plenumSheet metal plenum 1212 gaga. standard. standard

Some large ESome large E--style coolers will have 7style coolers will have 7 gaga. fan deck. fan deck


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Louver AssembliesLouver Assemblies Fabricated from aluminumFabricated from aluminum Teflon bushingsTeflon bushings

Internal or external torque tubesInternal or external torque tubes

Bug ScreensBug Screens

Made from polyester coatedMade from polyester coatednylon fabricnylon fabric

Attached with Velcro to facilitateAttached with Velcro to facilitatecleaningcleaning


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FansFans

Materials of constructionMaterials of constructionAluminumAluminum

SteelSteel

Nylon reinforced polyurethaneNylon reinforced polyurethane

Blade ShapeBlade ShapeAirfoilAirfoil

FlatFlat TwistedTwisted


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FansFans

Single pieceSingle piece Integral hubIntegral hub

No pitch adjustmentNo pitch adjustment

Fixed number of bladesFixed number of blades

Multiple pieceMultiple piece Separate hub and bladesSeparate hub and blades

Usually allow for pitch adjustmentUsually allow for pitch adjustment Can vary number of bladesCan vary number of blades

Often are resilient mountedOften are resilient mounted


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FansFans

Air flowAir flow Increases with pitch until stall is reachedIncreases with pitch until stall is reached

Increases linearly with speedIncreases linearly with speed

Decreases with ambient temperature increaseDecreases with ambient temperature increase

Decreases with elevation increaseDecreases with elevation increase Increasing fan speed will increase HP required byIncreasing fan speed will increase HP required by

the cube of the speed ratiothe cube of the speed ratio

The static pressure will increase with the squareThe static pressure will increase with the square

of the speed ratioof the speed ratio


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High Performance FinsHigh Performance Fins

ACE utilizes a high performance fin (HPF), toACE utilizes a high performance fin (HPF), to

enhance the airside performance of the finnedenhance the airside performance of the finnedtube.tube.

ACE offers fin heights unique among those thatACE offers fin heights unique among those that

utilize the enhanced fin design.utilize the enhanced fin design. This enables ACE to provide the smallest footThis enables ACE to provide the smallest foot

print in the industry, or increased cooling whenprint in the industry, or increased cooling whenreplacing sections in an existing cooler. This isreplacing sections in an existing cooler. This is

an especially important factor when shippingan especially important factor when shippinglimitations are critical.limitations are critical.


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InstallationInstallation

Inspect Cooler for DamageInspect Cooler for Damage Orient cooler so the fan air flow is in the sameOrient cooler so the fan air flow is in the same

direction as the prevailing summer windsdirection as the prevailing summer winds

Separate unitsSeparate units Avoid installing downwind of obstructions thatAvoid installing downwind of obstructions that

can affect airflowcan affect airflow


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StartStart--upup

Before any start up procedure is begun, aBefore any start up procedure is begun, athorough inspection of the Air Cooledthorough inspection of the Air Cooled

Exchanger should be made.Exchanger should be made.

1. Be sure all bolted connections are properly1. Be sure all bolted connections are properlytightened.tightened.

2. Inspect all process connections, as well as2. Inspect all process connections, as well as

vent, drain, temperature and pressure, or anyvent, drain, temperature and pressure, or anyother auxiliary connections, to be sure theyother auxiliary connections, to be sure they

are plugged or connected properly.are plugged or connected properly.


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StartStart--upup

3. Verify that the process sections are protected3. Verify that the process sections are protectedwith a safety relief device that has thewith a safety relief device that has theappropriate relieving capacity and a set pressureappropriate relieving capacity and a set pressurenot to exceed 110% of stamped MAWP.not to exceed 110% of stamped MAWP.

4. Prior to starting the process fluid through the4. Prior to starting the process fluid through thesections, check mechanical equipment.sections, check mechanical equipment.

a. Thoroughly check the plenum and fan drivea. Thoroughly check the plenum and fan drive

area to be sure all tools and constructionarea to be sure all tools and constructionmaterials are removed.materials are removed.


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StartStart--upup

b. Rotate the fan by hand and check fan tipb. Rotate the fan by hand and check fan tipclearance and alignment of belts and sheaves.clearance and alignment of belts and sheaves.

c. Check that the fan has been installed to matchc. Check that the fan has been installed to matchthe design fan rotation.the design fan rotation.

d. Check belt tension.d. Check belt tension.

e. Check all fan drive bolts to be sure they aree. Check all fan drive bolts to be sure they areproperly tightened. This includes bearing bolts,properly tightened. This includes bearing bolts,

fan and sheave bushing bolts, set screws, motorfan and sheave bushing bolts, set screws, motorbolts and fan blade attachment bolts.bolts and fan blade attachment bolts.


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StartStart--upup

f. If adjustable pitch fans are provided, check fanf. If adjustable pitch fans are provided, check fan

pitch and repitch and re--pitch per manufacturer's instructions ifpitch per manufacturer's instructions if

required.required.

g. If air operated louvers are provided, disconnectg. If air operated louvers are provided, disconnect

the air motor linkage and cycle the louvers by handthe air motor linkage and cycle the louvers by handto assure there is no binding or obstruction of theto assure there is no binding or obstruction of the

louvers blades. If binding occurs, check to be surelouvers blades. If binding occurs, check to be sure

louver frames are square. Attaching bolts maylouver frames are square. Attaching bolts mayhave to be loosened and frames shifted to easehave to be loosened and frames shifted to ease

binding. If louvers operate smoothly, reconnect airbinding. If louvers operate smoothly, reconnect air

motor. Cycle the air motor, using plant air and anmotor. Cycle the air motor, using plant air and an

air regulator.air regulator.


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StartStart--upup

h.h. If manual operated louvers are provided, checkIf manual operated louvers are provided, check

for binding of the blades, as in instruction (g).for binding of the blades, as in instruction (g).Operate louvers to be sure there is no linkageOperate louvers to be sure there is no linkageobstruction or binding.obstruction or binding.

i. If the fan is motor driven, bump test the motor toi. If the fan is motor driven, bump test the motor tomake sure the motor rotation matches themake sure the motor rotation matches thedesign fan rotation.design fan rotation.

j. After all the applicable steps previously statedj. After all the applicable steps previously statedare completed; the mechanical equipment mayare completed; the mechanical equipment maybe cycled.be cycled.


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StartStart--upup

k. Be sure all personnel and equipment are awayk. Be sure all personnel and equipment are awayfrom the fan and fan drive area. For safetyfrom the fan and fan drive area. For safetyreasons, equipment guards must be installed.reasons, equipment guards must be installed.Activate the drive motor and let it reach speed.Activate the drive motor and let it reach speed.

Check for vibration and excessive noise. IfCheck for vibration and excessive noise. Ifvibration or excessive noise occurs, immediatelyvibration or excessive noise occurs, immediatelyshut down, and check for loose connections orshut down, and check for loose connections orinsufficient clearance between moving parts. Ifinsufficient clearance between moving parts. If

the system is running smoothly, move to the nextthe system is running smoothly, move to the nextdrive and repeat above steps.drive and repeat above steps.


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StartStart--upup

5. Start the process through the tube5. Start the process through the tube bundle(sbundle(s).).Open the inlet valves slowly and let theOpen the inlet valves slowly and let the

processprocess WarmWarm the bundles slowly. This willthe bundles slowly. This will

allow the components of the tube bundle toallow the components of the tube bundle to

expand at the same rate and lessen theexpand at the same rate and lessen the

thermal shock.thermal shock.


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Routine MaintenanceRoutine Maintenance

Check set screws and bolts in the fan driveCheck set screws and bolts in the fan driveassembly and set screws in locking collars ofassembly and set screws in locking collars ofall bearings and sheaves prior to starting theall bearings and sheaves prior to starting theunit and again several days after start up.unit and again several days after start up.

VV--belt drives should be periodically checkedbelt drives should be periodically checkedadjusted until tight enough to preventadjusted until tight enough to preventexcessive belt slippage. The belt is generallyexcessive belt slippage. The belt is generally

tight enough when it can be twisted onetight enough when it can be twisted one--quarter of a turn with the thumb and forequarter of a turn with the thumb and fore--finger.finger.


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LUBRICATIONLUBRICATION Bearings should be greased in accordance withBearings should be greased in accordance with

normal maintenance practice.normal maintenance practice. OverOver--lubricationlubrication

is the most common cause of bearing failure.is the most common cause of bearing failure.In general, about one cubic inch of grease inIn general, about one cubic inch of grease in

each bearing every month is adequate.each bearing every month is adequate. TheThe

operating temperature of the bearing mayoperating temperature of the bearing may

indicate how much lubrication is required.indicate how much lubrication is required.


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Normal temperature may range fromNormal temperature may range from cool tocool towarm to touchwarm to touch up to a pointup to a point too hot to touch fortoo hot to touch formore than a few secondsmore than a few seconds depending on bearingdepending on bearingsize and speed, and surrounding conditions.size and speed, and surrounding conditions.

High temperature accompanied by excessiveHigh temperature accompanied by excessiveleakage of grease indicates too much grease.leakage of grease indicates too much grease.High temperature with no grease showing at theHigh temperature with no grease showing at theseals, particularly if the bearing seems noisy,seals, particularly if the bearing seems noisy,

usually indicates too little grease. Normalusually indicates too little grease. Normaltemperature and slight showing of grease at thetemperature and slight showing of grease at theseals indicates proper lubrication.seals indicates proper lubrication.


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TUBE CLEANINGTUBE CLEANING Operating conditions sometimes cause anOperating conditions sometimes cause an

accumulation of dirt on the outside fin surface.accumulation of dirt on the outside fin surface.This can be removed by directing compressedThis can be removed by directing compressed

air, or a greaseless solvent followed by a waterair, or a greaseless solvent followed by a waterspray through the fins in a direction opposite thespray through the fins in a direction opposite thenormal air flow. The inside of the tubes willnormal air flow. The inside of the tubes willrequire periodic inspection and cleaning asrequire periodic inspection and cleaning as

necessary. Removal of access plugs allowsnecessary. Removal of access plugs allowsvisual inspection, and if necessary, the use ofvisual inspection, and if necessary, the use ofmechanical tube cleaners.mechanical tube cleaners.


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PLUG LEAKSPLUG LEAKS Should tapered plugs develop leaks, additionalShould tapered plugs develop leaks, additional

tightening is normally all that is required.tightening is normally all that is required.

Thread dope may be used if tightening alone isThread dope may be used if tightening alone is

not sufficient. If shoulder type plugs developnot sufficient. If shoulder type plugs develop

leaks, the gaskets should be replaced.leaks, the gaskets should be replaced.

Tapered plugs that are removed for the tubeTapered plugs that are removed for the tube

inspection or cleaning should be replaced ininspection or cleaning should be replaced inthe same hole.the same hole.


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Routine MaintenanceRoutine MaintenanceTUBE LEAKSTUBE LEAKS

Tube leaks can be of two types: (1) leaks in theTube leaks can be of two types: (1) leaks in thetubewalltubewall itself (usually corrosion) and (2) leaks initself (usually corrosion) and (2) leaks inthe tube tothe tube to tubesheettubesheetjoint. In the first case, it isjoint. In the first case, it isusually most practical to plug both ends of theusually most practical to plug both ends of the

tube. When enough tubes have been pluggedtube. When enough tubes have been pluggedthat performance is affected,that performance is affected, retubingretubing will bewill benecessary. If leaks develop in the tube tonecessary. If leaks develop in the tube totubesheettubesheetjoints, rejoints, re--rolling of the tube will berolling of the tube will be

required. Care must be used in selection of therequired. Care must be used in selection of theproper tube expander for the size and BWG of theproper tube expander for the size and BWG of thetube being used. As with all rolled tube joints,tube being used. As with all rolled tube joints,overover--rolling must be avoided.rolling must be avoided.


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GENERALGENERAL If it is ever necessary to contact our plant forIf it is ever necessary to contact our plant for

service or replacement parts, it is essential thatservice or replacement parts, it is essential that

our serial number or other identifying data beour serial number or other identifying data be

obtained from the metal nameplate attached toobtained from the metal nameplate attached to

the cooler. This is the only way to positivelythe cooler. This is the only way to positively

identify the correct parts that may be required.identify the correct parts that may be required.

Air Cooled Service Basics 1

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