lrv p troubleshooting

5/20/2018 Lrv p Troubleshooting

1/6

SIHI LIQUID RING VACUUM PUMP TROUBLE SHOOTING GUIDE

IDENTIFIED

PROBLEMCAUSE EFFECT CORRECTIVE ACTION

EROSION

Characteristics:smooth, clean,groovedsurfaces andedges.

Presence of sand,

grit and otherabrasive material.

Accelerated wear of

impeller bladesespecially at theperiphery. Prematurewear of intermediateplate, centerbody &endcover(s).

1. Filter the service

liquid.

2. Add pre-separators atthe pump inlet.

3. Select proper pumpmaterials.

CORROSION

Characteristics:Usually

uneven, scaledon blackenedsurfaces andedges. Willoccur on allwetted areasincludingimpeller bladeroots.

Chemical attack ofwetted pump parts(usually by acidiclow pH). Sourcesmay be vapors orliquids from theprocess or from theservice liquid.

Accelerated damageof the impeller,intermediate plates,center body &endcover(s).

1. Monitor service liquidpH & treat asnecessary.

2. Purge the serviceliquid loop on a regularbasis.

3. Look for source ofcorrosives and treat orremove.

4. Change to a pumpmaterial e.g. stainlesssteel, that will notcorrode.

FLOODING

THE PUMP

1. Serviceliquid rateis too high.

2. Pumpstartsflooded.

3. Carryoverfrom theprocess.

Impeller bladesfatigue failure ofshaft. Shaft deflectionin single actingpumps possible,leading tomechanical sealleakage, high motoramperage.

1. Check the serviceliquid rate for thespecific pump.

2. Piping may beinstalled incorrectly.Pump should drain tothe centerline aftershutdown.

3. Check for properpump inlet separation.

CAVITATION

DAMAGE

1. Liquidtemperature too high.

2. Vacuumtoo high.

Holes or pitting at thetips and roots of theimpeller blade andintermediate.Grinding noise whenpump is running.

1. Lower the serviceliquid temperatures orincrease the flow ofservice liquid.

2. Lower the vacuumlevel. (increase thepressure)


2/6

VIBRATION 1. Incorrectinstallationoffoundation

2. Poorcoupling orV-belt drivealignment

3. Slugs ofwatercarry-overto thepump inlet.

4. Pipingstress atthe inletdischargeor serviceliquidconnections.

5. Pumpingestedforeignmaterial i.e.

bolts, nuts,weld slag.

6. Internaldamagedue tocavitation,corrosion,etc.

Broken couplings,worn V-belt drives orbroken foundationbolts.

Pump bearings may

fail prematurely.

1. Check with SterlingSIHI on properfoundation andgrouting procedures.

2. Check alignment or

call Sterling SIHI forassistance.

3. Check for proper pre-separation

4. Add flexibleconnections ifnecessary.

5. Pump should be sentto Sterling SIHI forrepair. Inlet screensshould be installedbefore pump is startedto insure material doesnot enter pump.

6. Repair or replace worn& damaged parts.

INGESTION

DAMAGE

No inlet screens onthe pump orcompressor

Broken impellerblades or seizedpump.

Return pump to Sterling SIHIfor repair evaluation.

SCALE Hard service liquidsi.e. lime or mud.Pumps runninghotter willaccelerate thisproblem.

a. Scaling willclose theinternalpumpclearances &causebinding.

b. Scaling willcause adecrease in

pump

Use suitable descaler, butflush after use. Consult withSterling SIHI for recommend-ations on the type andquantities.


3/6

performance.

c. Scaling willslowly closethe serviceliquid lines

and causethe pump torun warmer.

BEARING

FAILURE

1. Not usingtherecommendedlubricant.

2. Over orundergreased.

3. Couplingsor V-beltdrives notproperlymounted oraligned.

4. Piping notproperlysupportedand/oraligned.

5. Water inthebearings.

6. Internalpump

clearancessetimproperly.

Seized pump andbroken or damagedbearing housing.

1. Check the SterlingSIHI manuals forrecommendedlubricant.

2. Check & cleanbearings. (replace ifworn)

3. Check alignment &foundations for propersupport.

4. Use flexibleconnections for pumpinlet, discharge andservice liquid lines.

5. Check mechanicalseals or packing.Shield bearings ifenvironment is wet.

6. Consult Sterling SIHIfor assemblydimension or return forrepair evaluation.


4/6

PUMP RUNS

WARMER

THAN

NORMAL

1. Insufficientserviceliquid flow.

2. Carryover

of hightemperature liquids.

3. Carryoverof hightemperature gases.

4. Pump RPMmay behigher thanrecommended.

Capacity levels forthe vacuum pump orcompressor maydecline. Also thevacuum level mayfall.

1. Check the manuals orcall Sterling SIHI forthe proper serviceliquid flow.

2. Check for proper pre-

separation or call aSterling SIHItechnician.

3. High gas temperaturesmay be a processcondition that may beunavoidable. Adjustservice liquid flow asrequired. Call SterlingSIHI if problempersists.

4. Check pump RPM forthe service. Call ifnecessary.

PUMP LEAKS 1. Leakingpacking ormechanicalseal. Notesome

leakage isnecessaryto keep thepackingcool. (Overtighteningwill harden,becomehot & scorethe pumpshaft.)

2. Leakage

could befrom thebody, bodygaskets ordrain plugs.(Sometimes a result oferosion orcorrosiondamage.)

Loss of service liquid.Potential gas leakagewhen shut down. Inminor cases this maybe a house keeping

problem. In majorcases this may leadto poor pumpperformance ordamage to the pump.

1. Check packing andtighten or check &replace mechanicalseal. Service liquid orcontaminates from the

process can coat orabrade mechanicalseal faces.

2. Check the source ofthe leak. Repair may

be necessary.


5/6

HIGHER

THAN

NORMAL

PUMP NOISE

1. Pump iscavitating.

2. Pump isoverloadedwith liquid.

3. Pump hasingestedforeignmaterial.

4. Bearingsare in poorcondition.

5. Pumpcoupling orV-belt drivemisalignment.

An unusual or highnoise level is an earlyindication of aproblem. Thisproblem may lead topump damage or

failure. Potentialvibration concerns.

1. Cavitation can be acomplex problem.Consult with SterlingSIHI for solutions.

2. Check for properservice liquid flow.Also check for goodinlet pre-separation.

3. Stop the pumpimmediately. Dis-assemble and inspector send the pump toSterling SIHI for repairevaluation.

4. Inspect bearings. Seethe subject of bearingfailures.

5. Coupling and V-beltdrive alignment mustbe checked.

VACUUM

LEVEL

PROBLEMS

1. Poor pipingdesign.

Vacuum orcompressed airrequirements andpumps mayhave beenaddedwithout therequiredpipingupgrades.

2. Warmerthanrecommended serviceliquidtemperatures.

3. Incorrectserviceliquid flow.

4. Liquid

Vacuum levels thatare usually lower

than required.

1. See the sectiondedicated to piping

design.

2. The addition of heatexchangers, coolingtowers or chillers maybe required. Consultwith Sterling SIHI.

3. Check the manuals orcall Sterling SIHI forproper service liquidflow.

4. Check for proper pre-separation.


6/6

carryoverto thepump inlet.

5. Improperpump

application.

6. Poor orinsufficientvacuumcontrol.

5. Check applicationneeds and call SterlingSIHI for assistance.

6. Consult with SterlingSIHI for sizing and

selection of reliefvalves or revisedvacuum control needs.

lrv p troubleshooting

Documents