sadc

SECONDARY AIR DAMPER CONTROL(SADC) C.R.PAL,Sr Mgr(PS)

Secondary Air Damper Conro!(SADC) i" an imporan and "a!ien #ea$re o# modern CE de"ign corner%#ired &oi!er. 'e no o# ind&o damper" are $"ed o di"ri&$e air in *e #$rnace #or &eer com&$"ion.T*e +ery  p$rpo"e o# SADC SADC i" no o conro! conro! "econdary air air #!o &$ i" di"ri&$ion. di"ri&$ion. Pre%"e +a!$e o# '$rnace o ind&o(-) dp i" mainained  &y mod$!aing mod$!aing - damper" and *ere&y *ere&y mainaining mainaining #!ame a de"ired de"ired  po"iion a #$rnace. #$rnace. '$e! e!e+aion e!e+aion damper" are are ad$"ed o ge ge a "a&!e #!ame #rom a&o$ /00 mm aay #rom *e no11!e. More #$e! air "*i#" *e #!ame #$r*er aay and ma2e" #!ame $n"a&!e 3 !e"" #$e! air re"$!" in  &$rning i*in i*in *e no11!e and *ence *ence re"$!" in o+er%*eaing. o+er%*eaing. T*ere are "i '$e!(Coa!) e!e+aion damper"(A,-,C,D,E,')4 damper"(A,-,C,D,E,')4 *ree '$e!%Oi!% c$m A$ Air damper"(A-,CD,E')4 damper"(A-,CD,E')4 and *ree A$ Air damper"(-C,DE,''). damper"(-C,DE,'').  Ano*er damper damper "i$aed a *e *e &oom%mo" po"iion, po"iion, name!y AA damper damper i" no conneced o SADC circ$i and operaed man$a!!y. I i" a!"o ca!!ed ani%"!ag damper d$e o i" $"e in conro!!ing "!ag #ormaion. I" opening i" a!"o decided &y *e amo$n o# &oom a"* com&$"i&!e.

In SADC, '$rnace o - dp i" mainained a 50 mmc! $po /06 &oi!er !oad(ie "eam #!o). I i" main!y re7$ired #or p$rging 3 +ery !i!e amo$n o# #$e! #!o a *a condiion. *en &oi!er !oad increa"e", *e dp i" ramped $p o 80 mmc! #or &oi!er !oad #rom /06 o 906 and  mainained a *i" !e+e!. T*i" +a!$e o# "a$raed - dp can &e increa"ed or decrea"ed *ro$g* a &ia"ing po, "i$aed on *e p!a7$e. Coa! e!e+aion damper" are de"igned o mod$!ae a" a #$ncion o# #eeder rpm. -$ a :TPS *e"e damper" are c!o"ed a" *e #eeder" are no gra+imeric and a" recommended &y -;EL(a#er a !o o# ripping *ro$g* '!ame 'ai!$re).'$e! Oi!%c$m%A$ air damper" i!! ac a" A$ air damper" "o !ong *ere i" no oi! &$rner a *a e!e+aion. A" "oon a" *e oi!  &$rner" are pre""ed ino "er+ice, *en *e"e damper" i!! open #$!!y(ac$a!y <06) o caer *e air demand #or *ig* Ca!ori#ic =a!$e #$e!. I i!! remain open $ni! *e p$rging i" comp!eed. A$ air damper" are re"pon"i&!e #or mainaining '$rnace o - dp and i!!  mod$!ae according!y. Damper" o# a!! 5 corner" i!! &e in "ame po"iion o# opening>c!o"ing.

Iner!oc2" ?. A$ air damper or '$e! oi!%c$m%A$ air damper" a any e!e+aion i!! c!o"e i# i" adacen coa! mi!!" are no in "er+ice and &oi!er !oad i" @/06. . In ca"e o# -oi!er ripping(ie M'R) or !o"" o# &o* ID>'D #an" a!! damper" i!! open #$!!y and conro! i!! go o man$a!. T*i" i!! a!"o occ$r in ca"e o# dp@50 mmc!.

In"r$menaion T*ere are o dp ran"mier"(T) name!y DPT? 3 DPT o ge '$rnace o  - dp. =a!$e" o# &o* T are "*on on *e BCP p!a7$e. Any one o# *e T i" "e!eced #or conro!. I# de+iaion &eeen o T are *ig*er *an a  pre"e +a!$e an ann$nciaion i!! appear 3 conro! i!! go o man$a!. -$ i i!! no occ$r i# De#ea Sic*("i$aed on *e p!a7$e) i" operaed. '$rnace o - dp can &e ad$"ed i* *e &ia"ing po on *e p!a7$e. Percenage opening(command) o# damper", dp "e poin and &ia"ing are on "*on on p!a7$e.

 Ac$a! damper po"iion i" $" *e re+er"e o# *e poer cy!inder  po"iion ie. I# poer cy!inder i" #$!!y c!o"ed, damper i" #$!!y open 3 +ice +er"a. 'rom o$"ide *e ind&o e "ee *e poer cy!inder" o operae. Logic poer o# SADC i" ?0 + DC. Sc*emaic diagram o# *e circ$i a" &e!o.

DPT1

 

DPT2

SELECTOR SW

SET-PT

BIAS

ield side

I/P

Control Roo!

Signal to 4 corners of Windbox