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203.743.6741 • 203.798.7313www.preferred-mfg.com
Instruments & Controls
Catalog 25
Instruments &
Controls
181
BURNERMATE UNIVERSAL INDUSTRIAL BOILER CONTROLLERSystemOverview
SystemOverviewFullyMeteredcombustioncontrolisnowavailable“offtheshelf”inaneconomical,pre-engineered,parameter-drivencontrol package.TheBurnerMateUniversal Industrialincludesthefollowingfeatures:
• Patented“PredictiveFullMetering”fuel-airratiocontrol• Cross-limitedActuator,“PositionPacing”• SinglePIDfuel-air,ratiotuning• Airflowtemperaturecompensation• Gasflowpressurecompensation• WindboxO2FGRTrim+FlueO2AirFlowTrim
TheBurnerMateUniversal Industrial also includesall ofthefeaturesintheBasicandExpandedversionsofBMU:
• PrecisehightorqueServoActuators(3ft-lb->720ft-lb,8sizes)
• FD,ID&FGRFanandBFWPumpVFDdrivecontrol• NFPA85compliantBurnerManagementSystem(BMS)
• IndividualInterlockAnnunciationwithadvancedLockoutDatastorage
• LowFire,FuelChangeover• FiringRate,FeedwaterandDraftcontrol• OilAtomizingPressurecontrolwithSetpointCurve• Large10”colorTouchScreenOITwithpre-programmed
graphics(Note:15”alsoavailableoncustomapplications)• Modbuscommunications
Typical Fully Metered BurnerMate Universal Industrial P & ID.
S
AE
PT
Gas
FGR
Draft
Oxygen
Draft
S
Boiler
Win
dbox
AT
Oxygen
VFDMotor
S
S
FreshAir
TE
FGR
FD
SAux 1
FT
TE
SGas
Aux 2S
S
FT
PT**
Oil
Steam
FEpulser
PT**
or dPAtomize
Oil
LT DrumLevel
SDrum
Feedwater
SDigester
Gas
FT
Fuel3
INDUSTRIAL
203.743.6741 • 203.798.7313www.preferred-mfg.com
Instruments & Controls
Catalog 25
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BURNERMATE UNIVERSAL INDUSTRIAL BOILER CONTROLLERSystemOverview
TheBurnerMateUniversal Industrial isavailableoff-the-shelf for immediate delivery, requires only wiring andparametersetuptobeoperationalandisNFPA85compliantandU.L.recognized.
Predictive Metering Combustion ControlThe BurnerMate Universal Industrial offers a patentedmeteringfuel-airratiocombustioncontroltechniqueusingauniquecontrolstrategyreferredtoas“predictivemetering”.The ideal combustion control strategymaintains a presetfuel-air ratioover theentire loadrangeofaboilerdespitechangesinfuelsupply,combustionairanddraftconditions,andalsoprovidesrapidloadchangeresponse.
Traditionalfullymeteredcombustioncontrolsystemshavethefollowingweaknesses:
• TwoPIDloopsarerequired,makingtuningdifficult• CrossLimitingLead-LagcausesAirRichoperationduring
Loadchanges• SluggishresponsetoloadchangescausedbyPIDand
CrossLimitingLead-Laginteractions• AirFlowmeterinaccuraciesatlowflowrateslimitBurner
turndowncapabilities• Flowmetermalfunctionsdisable theburner,or require
manualoperationuntilrepaired• Untilnow,FullyMeteredcontrolsystemswere“custom”
sotheirbenefitswerenotavailable“off-the-shelf”
Preferred’s patented “predictivemetering” combustioncontrolstrategycombinesmultiplefuel,air,andFGR‘as-commissioned’feedforwardcurves(whichpredictServo/VSDchangesduringaloadchange),withmeasuredflowratebasedPID fuel-air ratiocontrol that incorporatesarobustcross-limitedpositionpacingalgorithm.Predictivemeteringuses“as-commissioned”measuredfuelflowrateandairflowratecurvestoensurethatthePIDfuel-airratioremainsatthe“as-commissioned”fuel-airratiosetpointforeveryfiringrate.
Predictivemetering,combinedwith“positionpacing”logic,assuresmuchmore precise actuator positioning andassures thateachservo remains “oncurve”during loadchanges.Thisallowsthecontrollertoincreaseordecreasefiringratemorequickly,withoutconcernfor“fuelrich”or“fuellean”burneroperation.ThesestrategiesareofparticularimportancewhenappliedtosensitivelowNOxburnerswithnarrowlimitsofflammability.
Because “predictivemetering” combustion control usesboth the servo actuator position feedback and fuel andairflowmeterinputs,meteringcombustioncontrolcanbeselectively “turned” off at low firing rateswhereair flowmetersmaynotbeasaccurate.Mostimportantly,ifaflowmetermalfunctions,bysimpleparameterselectiontheBMUIndustrialcontrollercanbedirectedtooperateasaparallelpositioning combustion control systemwith oxygen trimuntiltheflowmeterisrepairedorreplaced.Traditionalfullymeteredsystemscanonlyberuninmanualwhenthereisaflowmetermalfunction.
BurnerMate Universal Industrial Predictive Metering Control Schematic
Air Flow Fuel Flow
A/B
Fuel-AirRatio
Setpointcalculator
PID
f(x)
f(x)
Fuel Valve FB
Fuel Flow
Air Flow
Air Flow SP
Low FlowPID
Disable
O2 Trim
f(x)
f(x)
f(x)
f(x)
+
FGR
Aux 2
FD
FDVSD
Aux 1
f(x)
Cro
ss
Lim
ite
d P
os
itio
n P
ac
ing
Firing Rate Demand
FGR
Aux 2
FD
FD VSD
Aux 1
Fuel Valve
Commission Mode Curves
BMU Servos:
203.743.6741 • 203.798.7313www.preferred-mfg.com
Instruments & Controls
Catalog 25
Instruments &
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183
BURNERMATE UNIVERSAL INDUSTRIAL BOILER CONTROLLERSystemOverview
Because“predictivemetering”ispre-programmedandonlyapplication-specificparametersetup is required tomakethecontrollerfunction,BurnerMateUniversalIndustrialismucheasier tocommissionandoperate than traditionalfullymeteredcombustioncontrolsystems.ThesinglePIDblock(ratherthanthetworequiredfortraditionalsystems)requiresthatonlyonesetofPIDvaluesneedtobetunedduringcommissioning.
Inputsfor“predictivemetering”combustioncontrolinclude:
• Combustionairflow• Combustionairtemperature• Fuel1Oilflow(pulseror4-20mA)• Fuel2(natural)gasflow• Fuel2(natural)gaspressure**• Fuel3(digesterorother)gasflow**
**Note:Thefuel3flow,gaspressurecompensation,andatomizingpressurecontroltransmittersallshareasingleBMUIndustrialinput.Onlyoneofthethreecanbeenabled(fieldselectable).
Fuelandsteamflowsarealsototalized.EachoftheseflowratesandflowtotalshasaModbusaddressfordisplayonthe localOITTouchScreenor remotely viaModbusonPlantDCSsystemOITs.
BMUIndustrialFuel-Air-FGRCrossLimitedPositionPacing“Positionpacing” is a unique featureof theBurnerMateUniversal Industrial thatassuresthepositionsofall fuel,air,andFGRServosandrelatedVSDspeedsremain“oncurve”duringloadswings.Positionpacinghelpsavoid:
• Periodsof lean combustion that can cause rumbling,vibration,orflame-outsduringfiringrateincreases
• Fuelrichconditionsthatcancausesmoking,burn-back,andexcessiveCOorunburnedhydrocarbonsduringfiringrate decreases
Withtraditionalfullymeteredcontrolsystems,thesolutiontotheseproblemsistoslowdowntheresponsetofiringrate changes, and to tighten “cross limiting lead-lag” toassurethatthefuelandairflowsremain“oncurve.”Forsuchsystems,itisnotunusualforlowtohighfireresponsetimestobe4-8minutes.
BMU Industrial “position pacing” assures that all servoactuatorsremain“oncurve”inthefollowingmanner:
• Allfuel,air,FGRservosandVSDsmovetogetherand“oncurve”--thereisnofuelorair“lead”or“lag”.
• EachServo andVSDhas precise position or speedfeedbacktoinsurethatalldevicesarecrosslimited.
• TheBMUIndustrial“knows”howfareachservoactuatorandVSD canmove in 0.5 seconds and uses “self-adaptive”positionpacing toensure that loadchangesnevercauseanyservoorVSDtolagbehindtheothers.
• Εvery0.5seconds,theBMUIndustrialexaminesallcurvesto“find”theservoorVSDworstcase0.5second“move”causedbyarequestedfiringratechange.
• Basedonthecurves,allotherservosorVSDstargetpositionsare“scaledback”toensurethatALLdevicesarrive“oncurve”attheendofthenext0.5secondmove.
BMUIndustrial“positionpacing”isfullyautomatic,providesforsafercombustioncontrol,drasticallyimprovedfiringrateresponsetimes,andrequiresnouseradjustments.
Description CatalogNumber
BurnerMateUniversalIndustrialchassis.Includesoxygencompensationinputs,andexpandedprocessorwithdraftandfeedwatercontrol.LCDKeypadshippedlooseforenclosure-mounting. BMU-2ZN1
Note:BMUIndustrialservos,scanners,oxygenanalyzersandflowtransmittersarerequiredforacompletesystem.
FD Damper
FD VSD
Fuel Valve
Position Pacing
0.5 sec travel
0.5
sec
trave
l
Two Servo Example of Position Pacing
203.743.6741 • 203.798.7313www.preferred-mfg.com
Instruments & Controls
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BURNERMATE UNIVERSAL INDUSTRIAL BOILER CONTROLLERSuggestedSpecifications
1. Quality AssuranceTheboilercontrolsystemshallbemanufacturedandsupportedintheUnitedStatesbyPreferredInstruments.Theburnerfuel-air-FGR ratio control systemand the burner flame safeguardsystemshallbemanufacturedand labelled inaccordancewithU.L.372,U.L.1998,andCSAC22.2#199.SimplysupplyingULrecognizedindividualcomponentsisnotsufficient.Theassembledcontrolcabinetasawholemustbeinspectedforproperwiringmethods, fusing, etc., andmust be labeled as conforming toUL508AandCSAC22.1#14.InspectionandlabelingshallbesupervisedanOSHAapprovedNationallyRecognizedTestLab(NRTL).ThesystemshallcomplywithNFPA85“RequirementforIndependence,”theflamesafeguardsystemshallbeprovidedwithindependenthardware,andshallbephysicallyseparatedfromthecombustioncontrollogic.2. Predictive Metering Combustion ControlA fully metered combustion control system with oxygencompensationand(optional)VSDcontrolshallbeprovided foreachboiler.Eachsystemshallbedesignedtoprovidecontinuousboiler operationwithin boiler design limitswith a high level ofsafetyandenergyefficiency.Fuelflow,airflow,andservopositionforuptoeightservoswillbecontinuallymonitoredandheld“oncurve” during boiler load changes. For convenient setup andfasterresponseto loadchanges, thefullymeteredcombustioncontrol logic shall contain only one PID loop.As required thesystemshallprovidecontinuousmonitoringandcontrolofsteampressure(orwatertemperature),andwaterlevel.Ifaflowmeterisoutofrangeorinoperative,thecontrolstrategycanbeswitchedtoparallelpositioning,byparameterselection.Thesystemshallbefullyintegratedtotheburnermanagementsystemtoprovidefullyautomatic,safeandreliablestartupandshutdown.3. Oxygen Compensation SystemProvide a boiler breeching mounted in-situ, zirconium oxideoxygenanalyzerforeachboiler.Extractivetypeoxygenanalyzersarenotacceptableforcombustioncontrol.Theprobeshallbeofasuitable length tosense theoxygen level in themiddle thirdof thebreeching.Allwettedparts shall bestainlesssteel.Theoxygenanalyzershall:• Includecontinuousself-diagnosticswithdiagnosticcodesfor
atleast10commonfaults.• Automaticallysendthe trimcontrol to the ‘null’positionand
trigger the alarmdry contacts in the if an oxygen analyzerfaults.
• Thedetectorshallbefieldreplaceablewithoutremovingtheprobefromthestackandshallnotrequirespecialtools.
• Theanalyzershallautomaticallyperformperiodicdetectorcellimpedanceteststobeusedbytheoperatorasanindicationofcalibrationshift.
• Analyzercalibrationshallbepushbuttonsemi-automatic(notrim pots) with English language prompts and diagnosticmessages.Analyzeroutputshallbefieldselectableas0-10%or0-21%withoutfieldre-calibration.
4. WindboxOxygenFGRControlThecontrollershallacceptananalog input forburnerwindboxoxygentobeusedasameasureoffluegasrecirculationrate.During commissioning, awindbox oxygen vs. firing rate curveshallbeestablished.Thecontrollershallmodulatethefluegasrecirculationvalve (or fluegasblowermotorVSD) tomaintainwindboxoxygenonthepre-establishedcurvedespitechangesinambientconditions.
5. Atomizing Media Pressure ControlThe controller shall accept an input for atomizing steampressure or atomizing steam/ oil differential pressure. Duringcommissioning, an atomizing steam pressure (or atomizingsteam/oil differential pressure) curveshall beestablished.Thecontrollerwillmodulateanatomizingsteamflowcontrolvalvetokeeptheatomizingsteampressureoncurveatallfiringrates.6. Flame Safeguard System (FSG)Integral to the control system furnished shall be a BurnerManagement System (BMS)/ FlameSafeguardSystem (FSG)controller.Thesystemshallbedesignedtoensurethesafestart-up, on-line operation, and shutdown of fuel firing equipment.Burner management system components shall be located inthe combustion control cabinet and shall be fully integratedforautomaticsequencingof lightoffandshutdown.For safetytheBMSmicroprocessorandBMSVDshallbeonaphysicallyseparatecircuitboard.
Microprocessor-based FSG shall provide: safety interlocks,flamemonitoringprotection,and timedsequences.Sequencesshall include forced draft fan start and stop, furnace purge,burnerlightoffandshutdownandpost-purge.TheFSGshallbecapableoffiringuptothreefuels(twogasfuels,oneoilfuel),onefuelatatime.Fuelchangeovershallbefromoiltogas,orgastooilfiringshallbeaccomplishedatlowfirewithoutboilershutdownperNFPA.A front-mountedpanelwithEnglish language, four line, twentycharacter LCD message display shall be provided to displayflame signal strength, startup and shutdown sequence status,alarm, system diagnostic, first-out messages and burnerhistorical information. Historical information shall include thestatusofalllimitsandservosforthelasttenlockouts.To ensure boiler low water cutouts are working correctly, thecontrollershallbecapableofperformingadailyautomaticwatercolumnblow-downtest.Theusershallselectthetimeofdayanddurationofthewatercolumnblow-downtest.Thecontrollershallensure the lowwater cutoff switches are functioning correctly,andalarmtheoperatororlockouttheboilerifitdetectsaswitchmalfunction.To prevent nuisance trips, the flame safeguard system shallaccommodate two flame scanners with one required toprove flame.The controller shall provide120VACor 24VDCscannerpower,andaccepttwoanaloginputsforflamestrengthindications.Flamesafeguardsystemshall includeoilgunpostpurgeforoilfiring.Reliablelowfirecutoffshallbeprovided.For additional nuisance trip protection, field adjustable timedelays shall be provided for F.D. fan start, fresh air damper,minimumairflow,lowdraftcutout,andfuelpressurelimits.Fivefield selectable auxiliary relays shall be included for commonalarm,auxiliaryfanstart,blow-down,flameon,fuelvalveopen,hotwaterpumporvalve.Toprotectagainstdryfiring,anoptionshallbeavailableforhighfluegastemperaturelockout.Toensureairswitchesarefunctioning,minimumairflowpressureswitchandpurgeairflowpressureswitchshallbetestedforsafestarting.
203.743.6741 • 203.798.7313www.preferred-mfg.com
Instruments & Controls
Catalog 25
Instruments &
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185
BURNERMATE UNIVERSAL INDUSTRIAL BOILER CONTROLLERSuggestedSpecifications
7. Feedwater ControlProvideaboilerwaterlevelcontrollercapableofsingle-,two-,orthree-elementfeedwatercontrolwiththeabilitytoautomaticallyswitch between control strategies dependent on systemdemands.8. Draft ControlThe controller shall provide two-element draft control using aPreferred Instruments JC-22XMTR draft transmitter. Burnerfiringrateshallbeusedasafeedforwardforimprovedresponseto loadchanges.Thecontrolshallprovidebothautomaticandmanualdampercontrol.Alladjustmentsshallbemadefromthefrontpaneldisplayinengineeringunits.9. Flue Gas Recirculation Valve ControlThe controller shall have a characterizable setpoint curve fordamperorvariablespeedfanoutputsignal.Allthelogicrequiredtoverifythatpre-purge,postpurge,light-off,andburnermodulatecycles are automated shall be provided within the controller.Alternatively,thecontrolwillregulateFGRaccordingtoapresetwindboxoxygensetpointcurve.10. Additional Control Requirements:• Minimumnumberoff(x)curvestobeprovidedperservo:6• Minimumnumberofpointsperf(x)curvetobeprovided:11• ColdFGR lowfirecutbackshallbeprovidedwhenFGR is
utilizedforNOxreduction.• Separate curves shall be provided for FD fan full speed
bypassofVSDincaseofVSDfailure.• Controllershall include thecapabilityof receivingaremote
firingrateinputandremotesetpointinput.• Controller shall include dual outdoor reset setpoint curves
(normalandsetback)• Controllershallincludewarmstandbystart/stopcycle.• Controllershallincludelowfirehold,andcoldstartwarmup
ramping.• All external or auxiliary power supplies necessary for
electronic transmitters (or final control element) shall beincluded.
• BoilercontrolsoftwareshallbeU.L.372/U.L.1998recognizedand inaccessible toprevent tampering.Unitcommissioningshallbebyparameterselection,notrequiringladderlogicorblockwareprogramming.
• Thecontrollershallacceptstandard4-20mA,1-5VDC,orRTD inputs for analog inputs.No special sensors shall berequired.
11. OIT Color Touch ScreenProvideasanoptionaten(10)inchOperatorInterfaceTerminal(OIT) designed to provide local operation, graphic display ofinformation, alarm message display, historical and real timetrending, remote controller tuning, x/y plots of fuel-air curvedata for intuitive commissioning, Ethernet connectivity andstandardinternetbrowserremotecommunication.TheOITshallcontainaminimumof75graphicpagesandbenetworkedtotheboilercontrolandburnermanagementsystems.TheOITshallprovidegraphicpagesallowing step-by-step commissioningofthecontrollerparametersusingEnglish languagepromptsandselections.The systemshall be an industrial hardenedoperator interfaceterminal.The terminal shallbewebenabledandallow remotemonitoringviaastandardinternetbrowserandsupportModbusTCP/IPMaster,TCP/IPSlave,RS-485ModbusMaster,BacNetIP,andEthernetcommunications.
12. High Torque Servo Features:• Easy pushbutton set-up, not requiring the adjustment of
internalorexternalpotentiometers.• Servozero,span,anddirectionoftravelshallbeaccomplished
bypush-buttonconfiguration.• Totallyenclosed,dusttight,andsplash-proofcovers.• Provideaseparatedirectactingdigitalservoactuatorforthe
fuelgasandfueloil.• Electrically isolated shaft position feedback potentiometer,
integralbrake,90°rotationin25seconds.• Theactuatorshallbecapableofbeingstopped,started,or
instantlyreversedwithoutlosingpoweroroverloading.• Servoactuatorpositioningaccuracy:0.1degrees.Servofull
strokesafestartcheckshallbeprovided.• For high torque applications such as watertube boiler air
dampers,servotorqueshallberatedminimum70ft-lbswith0.4degreeaccuracy.
• Noservofeedbackadjustmentsshallberequiredwithpush-button zero setup.Adjustable travel limit switches shall beintegral, with re-adjustment not requiring new fuel air ratiocurvere-entry.
• Servos shall be cycled during each light-off cycle, and thefeedbackfromeachservoshallbemonitoredtoensuresafeactuatoroperation.
• Servos shall be Preferred Instruments,model BMU-SM orBMU-UM(hightorque).