FLAME SAFEGUARn CONTRULS phần 8 pptx

062.'" SP"'A~ GENERATOR Ef:lERGIZEO IFLA"E OlTiCTOIl OHI FIG. 84- SYNCHRONIZATION OF A Q624A SOLIO STATE SPARK GENERATOR " . AND A MINIPEEPER ULTRAVIOLET FLAME DETECTOR. WIRING The voltage and frequency of the power s~ly cen netted to the Q624A must be 120 volts, 60 Hz. The chaSSis of the Q624A must be propfufy grounded at 9JI times, even dUrlngbench testing; otherwise, the device may bum out. Loosen the cover screw (Fig. 83) and remove the cover. Insert the 2leact.viras (NEC Class 1) through the knockout in the boltom at the cese and connect them fa the screw terminals on the terminal board, and to the terminal strip or wirIng sl.Jbbase 01 the flame safeguard control (refer to Ta- bla VII and Fig. 85 or 86). Terminals T1 and T2 on the Q624A must be connected to the prc:per terminals of the flame sa1ElQuard control, as given in Table Vll. If the name deteclof and the ignition transformer are nor properly Con- nected, the detector may sense ignition spark, which could cause a hazardous condition. TABLE VII-WIRING CONNECTIONS FOR THE 0624A SOUD STATE SPARK GENERATOR FLAMe SAFEGUARD 0624A CONTROL TER_ FLAME SAFEGUARD MODeL MINAL CONTROL TeRMINAL RA890G IU1d R4795 T1 • T2 l2 Apprtlprlate ignition terminal R4126 and R4127 T, lIS specified on ptDgrarrmel' Instruction sheeL T2 l2 l2 R4140 and R4150 T1 Appropriate Igntllon terminal lIS speci1led on programmer Il'I9tnJction sheet. T2 I R~'ace the cover and lighten the cover screw. Coo- necl the high voltage electrode (Fig, 83) to the ignition eleCtrode on the gas pilot bomB!. (The high voltaQEl eleC- trode may be a qulck-connect type, or it may have a threaded lerminal nut, depending on the model of the 0624A.) Use Honeywell Spec No. R1061012 Ignition ca- ble or eq.Jivalen1. (This wire is raled at 350 F [1T5 CJ for F'A £ TER ' BOUO ~ FEGu RO ,,.SIDE Qil CO"TRO' t 6 :£J " L2 T> ,,,, T,o TER""N"'L C, FL E SM[(],v RD CC"TR"'L, UE ""'''C.", TE INnAv" 'C" S,.UT 'DR tE ,N L OU''''''AT'O'' 8 TER"" ITR" o~ ",R'NG ~VB8"'~[ & vS[ NH <l"'~l I "'Ill'"'' ,,,. FIG. B5- 0624A CONNECTIONS TO AN RAB90G, R4795, R4126, OR R4127 FLAME SAFEGUARD CONTROL. n l TE L50 RO FEGVAIIO 'N~'O[ Q62 C"'''TRD' t & T! u~ 6 _I",,.01l0N TEll"'"'''' O' F,A"E ~AF£"v"'''o CONTROL SEE O , TE ,,,STRun,o,, SHEET 'Oil HR"'I"A' OE~'G"AT'ON. & TERM'N"'L ITRIP DR ""RI ~uBB n & VSE Ie ", ""RING " FIG. 86- Q624A CONNECTIONS TO AN R4140 OR R4150 FLAME SAFEGUARD CONTROL. continuous duty, and up to 500 F 1260 C] for intermittent use. 11 has been tested t02S.ooo volts.) The ignition caDle should not exceed 15 reel [4.6 metres] in length, CHECKOUT OF THE QS24A Aner Ihe Q624A installation has been compleled, the fol1owinQ checks should be made to ensure that the syslem is working pr~rly. IGNITION SPARK RESPONSE TEST The flame relay shOuld not respond lDull in) 10 ignition spark. To determine flame detector sensitivity to ignition spark. per10rm the following steps: 1. Shut off lhe fuel suj:pJy to Ihe pilot and main fuel valve(s) manually. 2. Slart the SYSlem f:7.j raising the controller set point or f:7.j pressirlQ the START button. 3. Energize lhe Q624A Sofid State Spark Generator so an ig1ition spark Is produCed between Ihe eleclrode and ground. 4. Check to be sure that ignition has nol occurred. rrttere should be no flame.) Repeal steps 1 through 3 until Ihere is no 1lame. 5. Check the flams relay on Ihe flame saf~rd control. 11 the relay has not pulled In. the system is ~ralirlQ prc:perly. Continue the cheCkout with the Pilot Turndown Test. 6. It the flame relay pUlis in, stop Ihe system, r~ace the Q6.24A. and repeat steps 2 through 5. 260 REMOTE RESET ASSEMBLIES 11110Z11 (FOA AA.,o's A,NO A.7n·Sf \187018 (FOA A.I'O·S) 11876011 (FOA A.l.0'S) 7. Ilihe flame relay pulls in after replacing the Q624A, stop the system, replace the flame safeguard control, and repeat steps 2 through 5. o. - 8. If the flame relay pulls in after replacing the name saf8QUard control, Contact the local Honeywell branch office. Remole reset assemblies provide the capability of re- selting the lockout (safety) switch in flame saleguard controls from a remote location. All example of this awlication 'IS where the flame safeg.Jard control is located on an inac- cessible roof or suspended from a ceiling with no catwalk. AIlother example is where the ftalT\El safeguard control is mounted in an explosion-proot enClosure; the housing is secured by many bolts. In all of these awlications, it is dif- licult to gel allhe resel buttQ1 on the 11ame safeguard can· lrol. so the ability to remotely r9S9t lhe lockout switch is highly desirable. Some insurance agencies and code bodies severely restricllhe use 01 remale reset assemblies, If there is any question, these aulhorities should be consulted prior to installation of the reset assemblies, REMOTE RESET COVERS Remote reset covers are heavy dUty metal covers with a remole reset assembly mounted 011 them. The cover fits over the flame safeguard control. The remote reset as- semtJly consists of a 120 Vall, 60 Hz solenoid, with a plunger Ihat is direCtly ali ,-,ed with the (esel bullon Q11he ftalT\El safeguard control. Connecled to the solenoid is a 17 inch [430 mm] length of 2-wire, flexible Conduit, plus 19 inches [480 mm] 01 exposed, insulated leadwires. Longer wires, spliCed to these 2 wires, are connected 10 a remote PUSh-bulton switCh, Pressing the push-bu!lon switch energizes the solenoid and activates the plunger, The plunger awlies pressure to the reset bullon on the flame saleguard control to reset the lockout (safely) switch. Flemote reset covers available are shown in Fig, 87, Honeywell part numbers are: 118701 a-for use on R4150 Flame Safeguard Pro- gramming Controls. 118702B-1or use on RA890 and R4795 Flame sate- guard Primary Controls. 198365A-for use on R7795 Flame Safeguard Primary Controls, 118760B-for use on R4140 Flame safeg.Jard Pro- gramming Controls. PILOT TURNDOWN TEST Refer 10 the flame safeguard control )nslnJclion sheel tor the exact procedure to be used in performing the pilot lurndown test. FINAL CHECKOUT After other checks have been completed, restore the system to normal operation and ooserve at least one complete cycle fo be sure of satisfactory burner operation. FIG. 87-REMOTE RESET COVE-FIS. 261 71·97558-1 •• To Install a remote reset CO'll8r, loosen the screw(s) in the old cover llf there Is one) and remove It. Allgl the sola noid plunger In the new cover with the reset button on the flame safeQ.JlHd control, and mounllhe cover. Make sure there !tiar leasl 1/4 Inch 16.5 mmj clearance 101" the plunger. Then tighten the cover screw(s). AI the deSired remOle location mount a momentary push-bullon swilch. The switch must be rated to carry at least 15 VA Ohe power qonsu~ion of the remote reset solenoi9). Connecl the push.outton swilch 10 lhe solenoid (Fig. 88). Do notUS&8 toggleswiteh; if laft in the "on" posi· tion. II wguld cause the lockout switch to remain in the "open" posilion. The solenoid plunger of the remote resel assembly must disengage from the reset bullon on the flame safeguard conirol In order for the lockout sWitch to ee>rTWlete the circuli inside the control. & PRO.,O' 0"~ONN'C1 ",AN, ANOOV'R~OAO PRonc·~,,~ ""' I A' RH ".O In. '0T< "Un 00"< 0'0" _TEO A'" VA In "0 ", A' O"'R<O ~, O "oLAno" c ~ FIG. 88- TYPICAL HOOKUP OF A REMOTE RESET ASSEMBLY. If addilional wire is needed to reach the push'bullon switch, splice it 10 the 2leadwires exlending from the flex- Ible conduit on the reset assembly (Fig. B7). Moisture-ra siSlanl No. '4 wire. suilablefor atleasf 167 F [75 C) If used with an RA8900r R4795 , or for all~1194 F 190 C] if used with an R4140 or R4150, is recommended for normal installations. The lockout switch can be reset right al the flame safeguard control by pressing the end of the solenoid plunger, or it CM be reselfrom lhe remole localion by presslnljlhe remOle push-bullcn switch. REMOTE RESET ASSEMBLY (PART NO. 118811A) FOR AN R4138C OR 0 This remote Jeset a.ssenbly Is very similar to the assembly used 011 Ihe ramote reset covers, except thai II does not have a flexible conduit around its leadwlres. and It has asolenoid arm (Fig. 90) which depresses lhe JoC~oul swllch reset bUIlDl'l on the R4138when the solenoid Is en- ergiZed. To mount the remole reset assembly on an R4138C or D Induslrial Flame safeguard Control, insert 262 the nut and washer 00 the remote reset assembly Into lhe hole in the chassis just below the loc~out switch on the R4138 (Fig. 89). Make sure the washer engages lhe Inside lip of the hole. Slide the remote reset assembly upward (as shown by the arrow) as far as it will go. Insert the mounllng screw and tIghten It securely (Fig. 90). Make sure there is a minimum of 1/4 Inch [6.5 rTVTI] clearance between the solenoid arm and the lockout switch reset bullon when the lockout swilcn is reset. Wiring and q:'lEIration 01 this assam· biy is the same as for the remote reset covers (Fig. 68). :,U' HANDLE ~ - .______LOCI<OUT 'I ~'.,:,-;- '"'''" ,,, r RE~QTE ~ RESET • I , ., ~_\. ASSEMIIl" • RAllS r· iJ. I CHASSIS "O,-E IN C"ASSIS \ NUT AND WAS"EIl "., FIG. 89-INSTALLING A '1BB'1A REMOTE RESET ASSEMBLY ON AN R4138. LOCKOUT SWorCH "ESU BUTTON ~O:~oJl J';l! SOLENOIO A __ - EMOTE RESET ASSEMBLV SOLENOID ' W'RE {2_(lLACKI ~~L MOUNTING CHASSIS r ) SCIIEW "u L _ FIG. 90-A '18811A REMOTE RESET ASSEMBLY INSTALLED. INTRODUCTION A Flame safeguard System inclu~ all controls and associated de~ces r8QJired far safe corrbustlon. 01 the lh(ee elements required for corroustion -fuel, air, and ignition-fuel is the easiest to control. The purpose 01 the valve train, then, is to control the flow of fuel into a combustion chamber so Ihal it burns evenly_ Even combustion conserves fuel, controls pollut- ant by producls, and provides the right amount of heal needed for the process. In addition. many ~roval bodies such as Underwrit- ers L aOOrator(es Inc., Factory Mufual (FMj, and Factory in- suranCe Association (EI.A.) issue co::ies for burning fuel safely. In this section, we will COYer the types of valves available and develop typical valva trains to be used in Flame safeguard Systems. TYPES OF VALVES There are four types of valves used with ffame safeguard equipment. They are the Manually Operated Valve. or the Automatic Solenoid. Diaphragm, and Motorized valves, Fig. 1. VALVES MANLiAL MOTORIZED DIAPHRAGM RVG 1.1-1 FIG. 1-VALVES USED WITH FLAME SAFEGUARD EQUIPMENT. MANUALLY OPERATED VALVES Although most valva trains reqJlra automatic operation, the manual valve, Fig. 2, still provides corwenianl fuel shutoff for temporary maintenance or service. Manual shutoff valves are used in oolh the main and pilot fuel lines. This valve is also called a plug cock because 263 it consists of a tapered plug with a horizontal opening. As thEi manually operated handle turns thEi plug, gas llows through the opening. A V5050A FUElI Cock is anElIElclrically interlocking plug cock. The V5060A, Fig. 3, has two internal1nterlock switches that are connEicted to the Flame safeguard Car'llrol and sa1ely Shutoff Valve. These switches prEivent ignition of the pilot if thEi V5060A Valve is open. AflEir thEi pilot is ignited, the V5D60A may be manually cpaned to light the main burner. ArlolhEir type of valvEi is the Manual Reset safety Shut- off Va)~e commonly called a Free-hardle Valve. This valvEi closes automatically in response to Ihe Flame safeguard Controt, but must be opened by hand. An electrical circuit holds the valve open but cannot open it by itself. Af- ter thEi circuil is ElnEirgized, IhEi valve is ~ by hand and remains open until tl"lEl circull is de-energized. This PLUG COCK MANUAL SHUTOFF VALVE o FIG. 2-PLUG COCK MANUAL SHUTOFF VALVE. GAS LINE PLUGGED GAS FLOWING 71-97558-1 V5060A SUPERVISORY FUEL COCK FIG. 3-VS060A SUPERVISORY FUEL COCK. Free Handle Val e is used as the safety shutoff valve only In manually ignited systems where the burner is seldom shul down. AUTOMATIC VALVES SOLENOiD VALVES Of the three automatic valves. the Solenoid is the sim- plest and generally lhe least 8lCpensiv8. A controller opens the valve by running an electric current through a mag- netic coil, Fig. 4.lh6 coil, ac1lng as a magnet, pulls up the valve disc and allows the gas or oil 10 flow. Solenoid action provides fasl CIp!:lning and closing limes, usually less than one second in models wilhoul a thermistor delay. The V4046C Solenoid Valve is Widely used for safety shutoff valves in gas pilollines. The V8036 or V4Q36, Fig. S, is used in the main lines of smaJJ to maoum gas sys. lems. Unlike Diaphragm or Motorized Valves, the Soler noid is also used in ,:,il burning systems. Use a V4046A,B SOLENOID CO"TRCl'-'-~FI OPERATION !-I-CDJL VALVE DISC • • 5lF!?::;:·="~=,., ~I SOLENOID VALVES FAST OPENING AND CLOSING SMALLER APPLICATIONS V4QJ6, Veal6 FIG. S-V4Q36N8036 SOLENOID VALVES. for no heavier than No. 2 oil; and use a V4021A for heavy oil <lWlicallons. ALL of lhese are Solanoid valves. DIAPHRAGM VALVES Diaphragm Valves, like the DrI8 Shown in Fig. 6, are generally used on atmosph&ric typeo gas burners 10r smooth lightoN. These valves have a slow opening and last closing lime which deperdi on the amount of gas flowing over the diaphragTl. ThQ valve consists 0' a diachraam wifh a weiQ!l( over the valve seal. A small inlernal solenoid valve blocks the gas flow 10 lhe bleed port. When the COn/roJlef is not camnglor heat, Fig 7, the Coil is de energized. The plunger in the three-way actuator is In lhe DOWN position, 50 lhallhe bleed' port is closed and lhe supply port is opeM. Gas 1l0'NS to the top 01 the dia· ohragm. lhe gas pressure and the weight hold the valve closed. DIAPHRAGM VALVES SLOW OPENING-FAST CL.OSING USED ON ATMOSPHERIC GAS BURNERS V480R vsa ~v~ 113-7 FIG. 6-V48/88 AND V4843/B843 DIAPHRAGM FIG. 4-S0lENOJD OPERATION. VALVES. 71-97558-1 264 , PLUNGER WEIGHT DIAPHRAGM "'"' TO ~ SUPPl't/ PASSAGE TO BLEED PORT ~~~PLiy :~~ :::::::~:::=~:::==·=UJR_N_fR RVG 1]·11 VALVE CLOSED r~~-,GAS PLUNGER SUPPL v PASSAGE _ OIAPh'RAGM , " WEIGI;tT f TO BLEEO PORT MAIN - __ TO - GAS J BURNER SUPPL VL~~~ :-::::: ~=~:::==r- live &3-1 FIG. 7-S0LENOID VALVE - CLOSED. On a call lor heat, Fig. 8. Ihe controller contacts close and the coil is energized. This pulls the plunger to the UP p:>silion, opening the bleed port and closing the sl lWly port. The Qas then bleeds off the lcp at the diaphragm, allowing Ihe Qas pressure 'Qeiow \0 lift the diaphragm and open the val "'e. When aillhe Qas has bled off the lop of the diaphragn, Ihe valve is fully q::lEln, FIg. 9, permitting gas flow to Ihe main burner. After 1M controllar is satisfied, the proceclJre is re- versed. The controller contacts open so Ihal the coil is de- -,' energiZed. The plunger is released, moving \0 the DOWN p:>silion, FiQ. 10. This closes lhebleed pan and q::lBns the sUJ)ply port so that gas at;tain flows to the lop at the dia· VALVE OPENING PLUNGER WEIGHT OIAPHRAGM GAS SUPPL ." PASSAGE • TO BLEEO PORT MAIN TO GAS SUPPL I. V,. ~~: _::::,, ~,-~::;;;===.=UJR_N_f_R , FIG. a-SOLENOIO VALVE - OPENING. VALVE OPEN ~:==~ GAS PLUNGER SUPflL v WEIGHT PASSAGE DIAPHRAGM TO BLEED -" ~ PORT MAIN -'./ ' ' ~-! JTL.O- GAS ~ ./ ' BURNER SUPPLLy_-: _ :~:::c::=~~==:r- FIG. 9-S0LENOID VALVE - FULLY OPEN. MAIN VALVE CLOSED GAS FIG. 10-S0LENOID VALVE - CLOSEO. I:f1ragm. As the prBSSlJre alXNe the diaphragm increases, the diaphragm dtc:ps. closing the 't/al't/e with a posill't/Q. snap acllon. Diaphragm 't/al't/85 are CJ,liet ard ha't/(1 a reasonably long life. They are generally less expensi't/e than motor· ized 't/al't/85. Another ~ 01 diaphragm gas 't/al't/e is the COI'T"biM' tion 't/alve (Fig. 11). The basic q::l9falion of this If8I't/e is the same as already dBscrlbed, except thai it adds (or corn- billB5) other f\.lnctlons into one 't/al'tle txxly. The V484JIV6843B,C.L,N Valve Incorporales a single stage pt8S8U1'8 regJrator into the basic dlaphraQTi 't/al't/(1 desigl. The V4844/V8844B.C,L, N models pro't/lde two stage pressure reg.rlation. The one or two slages 0' pressure reg.rlation are used fa prO'ollde one or two staQ31iring rale control to the burner system. The V4843I\I8843P Val't/9 pro't/lde5 a intermittent pilol takeoff port. 2&5 71-97558-1 FIG 11-V4843fV8843 AND V4844fV8844 COMBJNATION DIAPHRAGM VALVES MOTORIZED VALVES Motorized valves perform two runclions-satety shutoff and firinQ rale control. We will discuss each 01 the fUnc- tions separately. SAFETY SHUTOFF 'vALVES Safely shutoff valves are usad for large gas burners Ihat require: 1. tighl closeoff. 2. accurate control of large MlOUnls 01 fuel. The Honeywell family 01 Safety Shutoff Valves \s shown in FiQ. 12. The VSQ55 valve Is controlled by a V4055, V4062 or 1,'9055 Fluid Power Actuator, FIQ 13, When the controller energizes lhB vaJvt acluator, Ihl) pump motor and dump solet'lOd are energized. The dUrrp valve closes to prevent ail leaking from the piston 10 Ihe aU reservoir. The PUm;l pulls oil out of the reservoir, and dischargas It into the piston urder prB$SUre. The oil pressure. In turn. forces the valve slem downward to open the valve, Finally, a limit switchstc:ps the pump molar when the valve is tully open. The valve pclSition. (open or closed) Is indicated through 1M windows on Ihe frO()t and side 01 the actuator. When the conlroller de-enerQizes the actualor, the dump valve opens. allowing me oil from the piston to re- turn to the reservoir. The V4Q55 actuator contains only a dump valve for ON- OFF cp9ralion. The 1/4062 OFF-lO-HI actualor and V9055 mcd; dating actuator, FiQ. 11" alse contain a bieed valve to control Ihe amount of gas flowing to the burner. The bleed valve contrds the valve stem travel stanlng at the low fire position, and continuos 10 cperate only when lhe aclualor is driving the valve cpen. Valva actuatols have 2 cpenlng tirnes- 13 and 26 sec- onds. Models with 26 second limi"g have a small molar and Ol"lly 1 pIston in lhepu~. MOdels with 13 sec()(Xj lim- ing have a large motor and 2 piston pumps. The different kinds of V5055 valves are shown in Rg. 12. The VSQ55D,E are used for high pressure applica· tions, while V5055A·C are for low pressure appllca:ions. Nole that the V4055 ON-OFF aCluator may be used with any varve. The V4062 OFF·LO·HI and the V9055 modulating valves must be used only on the v5055B with a characterized guide. HONEYWEll AUTOMATIC SAFfTV SHUTOFF VALVES ON·OFF lI~~ ;=o "5A ON OFF • V4055 ~J1 V5055D OFF-LO.HI HI PRESSURE _I aVji055B ~ CHARACTERIZED V4061 ~ ._-"'t + "''' GUIDE V5055E 1-4/ PRESSURE I 'V5055C . . 1; ~' " j .J FOR VALVE CLOSED __ ' INDICATION RV~ 83,'; V9055 FIG. 12-THE HONEYWEll FAMilY OFSAFETV SHUTOFF VALVES. 71·97558·1 266 V40SSA WITH VSOSSA 0" RESERVOIR -~- ACTUAT~ PUMP 1 OR 2 PISTONSI OP£RATOA PISTON VAlVE "OPEN" INDICATION VAlVE "SHUT"' INOICATION S10M SEAT DISC •• G" " FIG. f3-CUTAWAY VIEW OF AV4055A WITH A V5055A. V4062 AND V9055 PUMP MOTOR ANO DUMP VAlVE ASSEMBlY T f4E ON 0"" V40~5 HAS A DUMP VAlVE ONl V-NO BlEED VAlVE PUMP MOTOR Bl E, 0 VA.lVE OU"'P VAlVE , ' _ OUMP VAlVE SOlENOIO FIG. 14-INTERNAL VIEW OF V4062 OR V9055. A Characterized Guide (or skirted gJidel. Ag. 15. has notches or V's cut into lhe gJide to determine the valve flow characteristics. II provides a predictable relationship between stem travel and gas flow. As the valve varies the fuel, a c:lalTp3r linked to the valve actuator varies the corrbJstlon air. In this way. the valve ar1d actuator control both the fuel and air noodecl to vary the burner firing rate. The V4062N50SSB and the V9055,iV5055B seNe a dual purpose as safely Shutoff Valve and Firing Rate Control. These combinations may only be used on alm0scherlc burners where codes allow a dual fUr1ction 't'2tlve. For other applications a Bullerfly Valve IS used. whiCh will be dis- cussed laler. CHARACTERIZED GUIDE FIG. 15-A CHARACTERIZED GUIDE. The V5055C,E valves reQlJire a valve seal overtravel interlock (Fig. 16) 10 make sure the main fuel valve is closac! before allowir1g lhe ignition sequence to start. To accom- plish this, the V5055C,E valve with two seals is used with a valve-closed indication switch on tne valve actuator. The ~ switch can be wired to either make or break a circuit when the valve is in the closed position, VSOSSC, E VALVE SEAL OVERTRAVEL INTERLOCK "SHUT"" Ols.:: JUST PP.lOA TO STANDARD SEAl ClOSING Io':",,~ ElOTH VALVE SEALS ARE CLOSED sPECIAL VALVE SEAL ON VS05SC AND EONLY _~ SWITCH IN ACTUATES STANDARD VALVE SEAL ION All ",OOElS) FIG. 16-V5055C,E VALVE SEAL OVER TRAVEL INTERLOCK As lhe valve closes, the ~r seal CID8eS fi",t, step- ping the gas flow. The valve stem musl ·overtraveJ- pas! this point before lhe switch closes. Fir1ally the lower seal Is closed. The switch Is normally wired ir1to Ihe • Preignition Inter- lock· circuit at the Flame sa~rd Control to prevent ig- nilion unless the valve is ·proved- to be closed. FIRING RATE (BUTIEAFLY) VALVES (FIGS. 17 AND 161 By controlling the amount of fuel entering the bJrnaC. this valve determines the rale of combustion, or fIrlng rata. 71-9755&1 VALVE ___ CRANK ARM :; DFlIVE PIN STRAI'l RELEASE SPRI'lGS 121 ACTUATING ARM AI the same time, the valve actuator controls a damper which, in turn, controls the flow of combustion air 10 the burner. FIRING RATE VALVE COtlTROLS CO"8USTION 0" FIG. 17-0PERATION OF A FIRING RATE (BUTTERFLY) VALVE. BUTTERFLY VALVE V51E HINGED , , "8UTTERH Y" PLATE Oyo " "" FIG. 18-V51E BUTTERFLY VALVE. Other names for the cord)inalion firing rate valve and actualor are: Burner-ll'l)Ut Control Valve, Combustion Control Valve, MeterillQ Valve, Modulating Valve, Operat- illQ Valve, and ThrotWIlQ Valve. As mentioned be1ore, the V9055/V5055 Modulating Safely Shutoff Valve may be used fOf Ihis p,Jrpose, but be- C8Ll!ie mosl applications rBqJire single function valves, lhe V51E Butterfly Valve (Fig. HI) is mosl ofIen used. The V51E is combined with an M941 actuator and 0100 link· age. Since the V51 E Butter1ly Valve 00es not closetlghUy, a separate safely shutoff valve must be provided. The BL/tler1Jy Valve is named aner Its rOlaling hinged plata that reserrbles the opened wings 01 a butter1ly. This valve has a hiQh flow capaCity and relatively constant rela- liDnShip between fuel110w and the angle of alve ~illQ (Flg. 19). This feature IS useful for close modulation of air and fuel gases '0 large furnaces. An M941 Modulrol Ac- tuator (Fig. 20) controls the valve While simultaneously 0p- erating a corrbuslion air damper. Together, the valve and actuator provide a stable mixture of air and fuel. As the controller energiZes the M941 actuator, the in- creased resistance unbalances the molor bridge circuil. To correct the unbalance, the motor drives the linkage to rotale the hinged plate on the V51 E and open the Butter1ly Valve. The actuator continues to drive open until its feed- back potentiometer moves to rebalance the circuit and stop Ihe motor. VALVE OPENING ANGLE DIRECTLY RELATED TO GAS FLOW • · , ' " , " · " ~ u • D , , " ~_ 20 , V- I V i I / , I I / / ./ 0 10" 20" J()O 4D ° 50 60 • 70 • DPENI'lC ANGLE oyO" " FIG. 19-VAlVE OPENING ANGLE IS DIRECTLY RElATED TO GAS FLOW. FIRINGRATf "'""" FIG. 20-M941 MODUTROl MOTOR. 71·97558-1 268 VALVE TRAINS In this $eclion, we '1'111 davelcp a typical gas and oil valve lrain used in a Flame SafElQU3rd System. For spe- cific information on valv9 trains approved by various approval. bodias, see the Recommet'ldad Valve Trains setticn. GAS' VALVE TRAINS BAsIC COMPONENTS ~ shown in Fig. 21, the first and most Ilasic cDlT'PO- nenl Is the pipe, or gas line. used to carry gas to the combustion chamber. The gas 111 nol be Mowing continuously throu'tt!lhe pipe, 50 we need a manual plug cock to !urn the gas on or off t:If hand. Tl'1is plug cock is called thE! Manual Shutoff Valve (MSQVj. In a basic manual 1i{j110tf system. lhe operator ius! turns on the MSOV to start the gas r10Wlng into the combustion charrber. Then, he throws in a lighted match, rag. or piece of paper and stands back as the gas bursts Into Ilames. However, most applica(ions Icday reqUire a smoother, safer lightaff. So, we will acid a smaller pipe, the pilot line (FiQ. 22). An MSOV is required in the pilot iine, too. COM8\JsnON CHAM8E~ """ "" FIG. 21-BASIC COMPONENTS OF A VALVE - TRAIN.' MAIN~'=U~'~'='~",":'~l:.===::;:::;. GAS._ MsOV COMBUSTION CHAl.l8EIl: _vo n.,. M~V FIG. 22-EXPANDING THE BASIC VALVE TRAIN. 269 To 1lQ1l1he burner, we q)en lhe MSOV fn the pllof lIne and close lhe MSOV In the main line. Now the small plio! flame may be manually Ii'ttlled safely. When ttIe puot flame is going, the main MSOV Is cpened. The pllolflame lights the main gas as SOClf1 as It Erlters the ccmbuStion char'nl:ler. This manLli'lllightolf syslem works well as long as a per- son constantly watct'es the name. If the flame lJ)9S out ciJe 10 a pil (;03d gas line or some other undasirabJa occur- rence, he can close the valves and shul eXIwn the t;)Jrner. HO'l¥ever, it he does nol notice a name out siluatlon im- mediately, the cOl'TbJ:stion chan1:ler wilf nlf wilh urbJrned gas. lhe urbJrned gas, of course, creates a very danger- ous situation when the burner is rei(1lited. So, to walch over the flame, we need an automatic flame safeguard system wilhin the valve train. Our firsl corrpanent is a Safety Shuloff Valve (SSOV), FiQ. 23, 10 II~ • SAFETY SHUTOFF VALVE S OV .~o. FIG. 23-SAFETY SHUTOFF VALVE (SSOV.). automatically lurn the gas on and off. Notice tNt the syrrtJol used in Fig. 24 has a mile block above it This block represenls the actuator. We will also wanl a SSOV in the pilolline. Something musllell the Safety Shutoff Valve when to open and close the gas line. This is a logiC panel which In- etudes the Flame SatE9JSJd Control. Tnis conlrol is the heart Of the Flame Safeguard System, Fig. 25. Usually, GMi._ C"A.\I6UI MAl" BU~"ER l~":''t:kl==:t'J=.==:;::: CQM8USTIO", """ . ." FIG. 24-VALVE TRAIN WITH SSOV. 71·97558-1 [...]... FIG 26-THE FLAME DETECTOR WATCHES FOR A FLAME SSOV PILOT LINE COM8USTION CHAMBER FIG 29-SAFETY SHUTOFF 270 71-975 58- 1 Another point we must consider is providing gas to the burner at [he right pressure, Fig 30 Gas enters Ihe valve +UPSTlUAM DOWNSTREAM 10.00 ill R,OVCE 'R(~5UR( ~ 8~ '1' I· ~I\~ ~\ 'I WC~01~.SI 1Q ~SI" GAS FLOW'" _ FIG 32-LOCATION OF THE PRY Now we have an autOlT'l8l1c 5VS18m for lighllng... name If bolh the pilot and main flame go out (Fig 29), the ttame delector will break ils clrcuillo the Flame safeguard Control The Flame Sa1eglJafd Control, in tum, will signal UI"BU~"O~ C~"·", ."or U~I FIG 27-PILOT IGNITION '" CO~TROl II MAIN BUR~!" "N' ,~.- , ' FIG 28- MAIN BURNER IGNITION ,,,,or tiM CO"'BUS"o~ c~A"'8E~ '" FIG 25-THE FSG CONTROL IS THE HEART OF THE FlAME SAFEGUARO SYSTEM CONTROL SAFETY... need a Flame Deleclor (FIg 26) 10 walCtl for a flame in !he corrt:lustion charrber Now, to start the burner with our automatic valve train we first open both the Manual Shutoff Valves Then, when we need heat, the Flame Safeguard Control q:e1S the Safety Shutoff Valve iJ"lthe Plio! Une At the same lime, it turns on an ignitioJ"l sci-uce for the pilot, Fig Zl Wh8l'1 the flame detector sees the pilot flame, ... mmJ or larger, must be in stalled between the two SSOV's RECOMMENDED CONTROLS PILOT SAFETY SHUTOFF VALVE: V4046C, V8046C, V4036A,B, V8036A LOW AND HIGH GAS PRESSURE SWITCHES (required over 2.500,000 Bluh): C845, C437, C637, C447, C647 MAIN GAS SAFETY SHUTOFF VALVES: V 48 vas, V 484 3, V 484 4-Maximum ClosinQ time 5 seconcts, for under 2,500,000 only V4055A actuator wifh V5055A,B valve-maximum closing lime,... which watches tor flame in the cOlTtxJs lion chamber; the Main Burner Une and Pilar Une, which bring in the gas to be burned; and the Vent Une, which gets rid 01 leaking gas when the burner is shul cbwn Fig 50 provides a closer look al the Pilot Une The han- ThiS closeup of the Flame SafeQuard Control, Fig 48, shOws the Flame Signal Ampliffer, which makes the electri· cal signal from the flame detector... the Flame Deteclor This deteclor is a Honeywell C7012E Purple Peeper Ultraviolet Flame Detector The C7012E Is colored violet to indicate it is an ultraviolet detector CO BUSTIOIIi CHAMBER FIG 46-THE COMPLETED VALVE TRAtN Fig 47 shows the logic panel, which includes a Flame Safeguard Conlrol -Ihe hear1 ollhe system Nolice the in dicating lamps which show the status of the system 274 71-975 58" Flame. .. Boiler·Fur naces with One Burner" NFPA No 85 -1967 283 71·975 58- 1 FACTORY INSURANCE ASSOCIATION AUTOMATIC SYSTEM V(~l TO "'T"'OV~(R( "R' R T[ CO"TROL (O'T'O Lj { ~, • LOW!'!; ~ M~OV o o .,N • 8UR"E" • FACTORY INSURANCE ASSOCIATION SEMIAUTOMATIC OR MANUAL SYSTEMS vENT TO TMOl;"'(R( ~'R'N'" 10PTI0 VENT UAL ~SOV 1l T[ CONTROL LI { ssovwrT~ RE~ET M~OV o , 8V"'N('" BVRNER "RH~vIlE TEST ,,,, VENT V"'LVE... (he Flame Safeguard" Contralto ~n lhe Safely Shutoff Valve In the lllain burner line The pilol then 1i~IS the main burner, Fig 28 Once the main burner Is lit, we can Jeavethe pilot on or lurn il off If (he pilot remains burning while the main burn ar ~rates, it Isan intermillent pilot lnan inlarn ptedpilot system, the Flame Safeguard Control Signals (he pllol SSOV to close the gas line once the flame. .. Sat8Quards on Single Burner Boiler-Furnaces, 1963 revised National Fire Protection Association, "Standard lot Prevention of Furnace Explosions in Fuel Oil and Natural Gas-Fired Watertube Boiler-Furnaces With One Burner.' NFPA No 85 -1967 Also refer to these Honeywell summaries at Approval Body Requirements: Form 70 -82 14, Underwriters laboratories Inc R~ire ments for Gas and Oil Burners Form 70 -82 15,... use the V4{J21A as the safely shutoff valve (Fig 58) Additional samples or both gas and oil valve trains are found in Ihe Recommended Valve Train section f'~ING " U,TE CO TI'OL FIG 56-A OSI OIL SYSTEM 71-975 58- 1 HEAVY OIL VALVE TRAIN 'S(; CQ'HIIOl 'IIING RATE CONTROL IIEC,IICLolATI G VALVE • FIG 58- COMPLETE OIL VALVE TRAIN FOR HEAVY OILS 27B 71·975 58- ' RECOMMENDED VALVE TRAINS -"The foilowing vall/strains . to the burner system. The V 484 3II 884 3P Val't/9 pro't/lde5 a intermittent pilol takeoff port. 2&5 71-975 58- 1 FIG 11-V 484 3fV 884 3 AND V 484 4fV 884 4 COMBJNATION DIAPHRAGM. CL.OSING USED ON ATMOSPHERIC GAS BURNERS V 480 R vsa ~v~ 113-7 FIG. 6-V 48/ 88 AND V 484 3/B843 DIAPHRAGM FIG. 4-S0lENOJD OPERATION. VALVES. 71-975 58- 1 264 , PLUNGER WEIGHT DIAPHRAGM "'"'. Pro- gramming Controls. 1 187 02B-1or use on RA890 and R4795 Flame sate- guard Primary Controls. 1 983 65A-for use on R7795 Flame Safeguard Primary Controls, 1 187 60B-for use on R4140 Flame safeg.Jard

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