Document ZJ8yodEEyYQLQmQNeV2B9w9YZ

FILE NAME: ZK/L DATE: : DOC#: BO/L DOCUMENT DESCRIPTION: d:Z ".,.r " JU~Y 1 95 1 VOLUME 95 Opera/lnq NO. 7 combined wi,,, ENGINUR ENGINEERING AND MANAGEMENT The long look 'ahead-an editorial . 69 Crushers cinch fuel sizing and cleaning 73 Chemical feeding-direct to boilers 76 Electronics: Control for dc motors: Part 2 78 Th! balky ash-removal system-Case No. 2 in a series 80 .v.;cr'f midget produces piloting power 113 :l'1s"i:Jt:on cuts mercury-unit losses 150 POWER HANDBOOK-Part Two: Basic power services 81 feedwater chemistry c ...... .... " 1.. ~ ....... ~t....IIC'+: I v ... "I> .................................... . Steam generation Steam turbines Diesels & gas engines Compressors & fans Refrigeration 82 Heating 100 86 .AJr cor.d!tiordng 102 90 Heat-transfer equipment 104 92 Lubrication 106 94 Insulation 107 96 Electrical machinery 108 98 Ac converters 112 PLANT OPERATION AND MAINTENANCE BOILERS are hig hu"in .... " on thl' We"t Coa"t th.."e day". Long a hydro -trnn!!hold, California now turn .. to -It-arn po\\er 3, booming demand out.. trip, waler'power potential. Our ('o, ..r ('allh," thi" tr"n'! in an illl' pn'''"iw "hot of aB&: \'1/ radiant !wil"r at Pacific: Ca" &: EI...-tric'" \[0-'; wntling Sta tion. Wielding the ratchet hoist i-; a Illpmh"r of th, C C ~Ioore Co eredioa CCl'W. Boil"r is one. 0 f six -l7S,OO)lh,p,rhr unit" supplying three lOO,OOO-kw turbinegt'nerator,.. One of the,e machines has been operating ahout a year, olh"r two, see serviee ,;oon. \Vith two mort' turhinegenerators and their boilers plannl'.! for 1952, this 1300-p"i 9S0-F outdoor plant promises to be the largest west of the \li",.i:'sippi. But til,':'e day" who can tell ~ Slash handhole-plate time-Operators' Notebook No. 43 5cale scots fast now that cooling-water gets care Buying silent c',ain? Then you'd better start here Aim at best Oll ~ut for centrifugals Hot maintenance 1'1-' for propeller pumps H"re s how to build your own stroboscopic tachometer Pructical Ideas 130 How to Plant problems 136 Headwork Arguments 142 Marmaduke 118 .120 122 124 126 128 1 146 148 READER SERVICE SECTION , ~Iant [jr:ta ,heet: Number 229 152 equipment news 160 PJ'Ner news 154 Engineer's bookshelf 172 T.!chr:ical briefs 156 George Edwards 174 POWER Vol 95-No. 7 (Member ABC and ABP) ,':')'04 1 t.....: ,1 .f with whi,h arc con,solidatcd Scien~~ and ,Industry. Th~ E'}Kint'u Re~'l:t'w. T1t~ Engintt'" Tilt' i .~ rI " l-.If1t:IIlt'a and Opaalln~ Engfnt'a) IS published monthly with an addItIonal directory number I \ PL:BLl- r':~\ ~:r~\'ft:a~;~(W~:&_IU\'Lnc: B1:m)~'t~G.l~~o ~~~,,~ ~~'o/1,\v ~~6~iJ.9t~.) :l~~ndCr. ,- .. 'Le. T1\ E. EDITOR!.-\L and ADVERTlSI:-OOG OFFICES: JJO W 4:nd St. New York lB. N. Y. ~""r , \\, \1..:GrJ.w. Prcsid.ent: Willard Chevalier. E~cculi\e Vice-President: Joscph A Gcrardi. ViccI;'':.' .(~~ ..I~d Treasurer; John J Cookc. Secretary; Paul Mont(~omcTY. -?cnior Vice-President. PubUcations , t \~~~I.. ~~l~.h V~cc:Prl~~i'de;~it~ri~alD~~~~~O~{ ~fr~i'ati~~~d. Vice-President and Director of Adverusing; 11 ~. IlS'-'RIPTlO:O;S: Address correspondence to POWEa. Subscription Service. 330 W 4~nd St. :-OOcw York S ). Allo".' tcn days for change of address. Please indicate position and company connection on orders. 'f"'"~""; .n~1c COPies 50C. Subscription rates- U. S. and U. S. possessions: $4.00 for one year. $6.00 for two $..." t. 1.,n3Ja: $7.00 for one year. Sl1.00 for two years. All other countries: 515.00 for one year. S15.oo $/".-k .... 1) yeaN. Entered as s.econd-class matter January 26. 1949 at the post office at New York. N. Y. '\:1 r~:'~l~t r~~C~'~d~h 3. 1879. Printed in U.S.A. Copyright 1951 by McGraw-Hill Publishing Company. Int.:. t'.l ! J~~I':" t lit .:t.rtidt.!'.~ arc indexed in ~oth the. Industrial. Arts Index and the Eng/nt!t;ring Index. POWER .l \ It-!. o\o,.'n mJex annu311Y.,~oplt.!'s of whl~h are av;,:u13blc un n:qur,;st to the ctlilonal otfkcs. ------------------------------------------------------------------------~ Next month .. Right in the heat of the ba,,<'hall "ea"on we're pullin~ a trip1,' pia\' of our own. In Augu"t you'll find the lowdown on welJ,; and well pUlllpS in---(,lIullt ,'m! -three place,: basic fact .. in the E&\[ section, care and ~epair in PO&\I, tip" on testing in the Data Shed. Be ;:ure you cover all bases! _-\t Sewaren they've gone all out to g' .. t ma"illllllll ll1.1b'"~l !lllritv. '1'011'11 see why in _-\ugu,t', ,tory on how they treat city water for evaporator feed. Another .l/an 0/ Action story take,; YOU to Ea"tman Kodak's I-bwkeve plant. it'll,; you how Wavne Farrl'll keep" on top of his job of making thi .. plant top" in efficiency. cleanline-... Cot "om!' el,ttrit'otl "q"ip"lt'nt tu han;! 011 a w:.dl'~ Gr:lh Jim O'Collnor'" "hahy" "pt'cial -eetion Oil an('horsthat's where YOll'lI find all the n'~w wrinkles---and te"ted old onp:i-for doing: lhe joh !}ui,'kh' and easily. .. and future months Being readied for October: a 16-pg handbook on fans (both draft and ventilating l. It'll Ctlver ba"ic fan facts. types and arrangement .., construction, fan ch:uacteristics. drives and control. selecting and applying fan:', opt' rating and maintaining them. I i~ ,\'' I I'i I ! I I i j i I ! J i 11 fiGURING HEAT LOSS, ECONOMIC THICKNESS raWe*, lower right, shows loss for various .hicknesses of as~ magnesia insulation applied to pipelines or flat surfactS 300 deg F hotter than surrounding air. Data can be uJt<i approximately for such insulations as mineral wool at!d ~ponge-felted asbestos. If temperature difference is sreater or less than 300 F, apply factor from chart. I,XAMPLE: A 220-ft run of 4-in. pipe insulated with double- standard insulation carries process steam (saturated) at 600 psig through. a room at 80 F. What is hourly heat loss? Solution. Pipe temperature is 490 F, from scale, so tem- ptrature difference is 410 F. Factor from chart is 1.45. Loss per ft of pipe run at 300 F, from table, is 89.4 Btu. 10tal less is 89.4 X 1.45 X 220 = 28,500 Btu per hr. ECONOMIC THICKNESS. To figure economic thickness for insulation, draw up a table for the specific job similar to one shown below for a heater. Thickness, UKhc!i 0 . 1 1 ~';' 2 2 I, ' J Total insulation cost in:jtitl1ed $200 260 ' 318 374 429 Total yearly dollar 1055 $720 180 126 96 76 62 co.t of added insulation thick~es~ $200 60 58 56 55 Years (or Added added.a vsaving ing to pay Rd<\p<\ cost $540 0.37 54 1.11 30 1.93 20 2.80 14 3.92 Then pick the thickness that pays off in the time required by your plant's financial policy. If insulation above has to payoff within three yearg, use 2~-in. Fr'.llIl M&.6Desia Insulation Manu!&cturers A.aocl&tton. PRESSURETEMPERATURE SCALE I +: iO I I I 620 200 Gage pressure, psi 10 2I0 I 50 100 1 I1111I 150 200 I I 500 I II 1000 1400 III I I J I TEMPERATURE CORRECTION FACTOR (lIased on 300-deg F temperoture difference os normal) la 1.7 16 1.5 1.4 1.3 12 I. I 1.0 2 09 ~ 08 "- 07 0.6 05 V 0.4 Q.3 I..-'" V I 1/ V I Y 1 y' ./1 I I ./ I i V I I 1I V i .L I tL: ...... VI , i i ! 1 I~ 1 11- I i i 02 O. I o 00 2CO 300 400 500 Temperature difference, deg F dual." ,ttlyarepetJo." ',:! sed. 'c~: ',' petroleum. . ne soda.~. 11i~ soaps .~: )otassium.~" n in bear.J: ';ji; pressurd.l graphite, 0.-1' and yam ":' Icants. 'ones) re ,.Cl>" . undetl ~el1 ~:;!'I:lr propertieS; , avoidin& ,: ~: Iture addi- , -' .I~t.' important;Jf serving as ~~~' .~. '.~ '.;,J . {~~;:i. . cdMM'ERCIAL ,<.'.; I " ., IN$UL~TION>'.. ,- .;.>. -, .' KINDS ANO Sh 'PES .'", ., OF , e : HEAT INSULATION ... - ".,. FOR t .,., '" WARM SURFACES 0 I 0 ~ '" ... :;:; :> 0 0 ;;;~ "" ~ g.a ~ : ~ ." Q. c ~0 0 ]! Q. 0 V< :> c: g~ V< U :> - '" ",,; '" ~ E - E ~ Q0j :0:;: .I. 0V< ~ _0 00 0u 0 o ."'c": .Q " .SE:> g.8 .E:9 ~ ~ 0 0 c 0.= E E 2.:! o il.. <i <t IX) Q. V< f/) 0 ~ ~ u 0 <:'-'iJ 1 ""'" t@m~,.rytl)"f? 200 300 750 600 700 1000 1900 2500 r F F ,- r f f F :....:..ose or granulated .....- ...... ...... ~ ~ T.ent ...... ...... ..... ...,. ..... 3:anket~;'l 'A xHs -. - ~ V C d :-eets ,fleXible) 0t:fijJf! ~cards blocks 1st Iff) .:;- -=-- ~A,' VV VV ...... ..... V ~ .....- .....- ...... f!!!!!!!if'"' 'JaIded" ,egnents' ~ Shaped sections C.~ V Y ..... V Y V ..... Bricks E l ...... HEAT LOSS THROUGH 85 % MAGNESIA (Multiply by correction factor from above chart) Pipe Insulltion Heat size, thickness, loss, inches inches Btu' P,p, Insul.tion He.t SiZI, thiCKness, loss. inches inChes Btu' Pipe Insulation Hut size, thlcKnl!ss, loss, inches incnes Btu 1/2 7/8 (s) ~l.9 1112 40.8 1 29/32 (d,) 36.9 2 36.2 2 1/2 33.0 3 30.9 I 1/32 (s) g2.4 1 1/2 :4.0 2 63.0 2 S/32 (d,) 50.5 2 1!2 55.8 3 50.6 1 1/8 (s) 1nl 1112 138 2 \l) 2 5/16 (dl) 103 2 1/2 97 .~ 3 86.4 3/4 7/8 (s) ~9.1 1 1/2 4~.7 I 29/32 (ds) 41.1 2 40.2 2 1/2 36.~ 3 33.9 2 112 I !i32 (.) 106 I 1/2 !U 2 11.1 2 5m (ds) ;7.8 2 1/2 ;2.4 3 56.6 1 1/8 Is) 1112 2 2~,:6(ds) 2 liZ 3 195 158 I2S 117 III 97.8 718 (s) 67.l I 1/2 ~1.7 I 29/32 (ds) 46.1 2 IS.J 2I 1 40.' 3 37.; IV4 7,8 (si 79.5 1 1/2 ~9.2 119131 (ds) 51.4 2 SI.1 2 112 45.7 3 41.J 1 112 7/8 (s) 8&.7 1112 R2 I 29/32 (ds) SU 2 ~S.! 21!2 49.2 3 4~.O 11.32(') :13 I 1/2 %.9 2 81.0 2 5.32 (ds) 77.4 1 :.1 70,] 3 63.; 31.2 1 1 J2 Is) :37 1 1/1 :07 2 815 2\,31 (ds) 84.7 2 1.2 77.3 3 69.4 1 l.'8 Is) 141 1: 2 116 2 96.5 2 1.'4 (ds) 89. 2 1/2 83.6 3 74.7 11.'1 is) 2Z5 I 1/2 197 2 160 2 1. 1 ids) 136 3 119 10 1 L I ISI 2",. 1l.'Z 118 1 191 Itn (ds) 161 3 141 ~~ U.c .;:; .~ .!!.S !~i C:i~ 1 1 112 2 2 1!2 3 31/1 4 96.2-69.9 ~u 45.2 38.4 33.1 29.~ (s) SI..dard thickness lds' double-standard tllCkness. Btu per hour per !oot :;! pipe lenltn at 30(}-d~,F temperature dIfference. Btu ~r hour ~e, sQl:a~ foot of Insulatlol1 surface ~ 300~eiF temperature ditferencl!