Note: Descriptions are shown in the official language in which they were submitted.
II~AY. ~1. lhC1 ~:'''P~ r~ HE~ A~o2~2Aoh6~2~ 1997-06-03 NO i~6 P. 3/~4
~TR~T~. F.r.F.l~l~,NT ANI~ f~ i, FnR fCO~/IRUSTIO~ PT ~T-C
Tl~e present invention relates to ~ grate element for a ~ng grate constIucted of ~ate
- ~Ic,ll~nt~ which overlap each other li~ce roof tiles and ~n move lon~i~din~lly re,~i~e to
each Gther, through wbich the pnmary ~vmbustion air, which is fed from below, can be
guided to the m~r~9n~1 t~ be bume~ which is lying on top of the fin~g grate, with ~
s.~l~cl,~ f or dn~e e;ld and a g~a~e element head The invention also relates to a ~te fo~ a
combust~on p~nt and a process for oper~ring the grate.
I'he te~ "grate eleme~t" is to be unde~s~ood as applyin~ to eYery ele~ent which is suitabl~
for fo~ning a ~te floor, independently of whether i~ cooled or ~ wa~e~-cooled grate
floor, i~l~syective of the constmc;ion of the ~rate finn~ system, 50 ~OI~g ~S it employ~ gr~te
e~ements which overl~p each other like rwf tiles to ~nn g~2tin~ stages.
~ e floors whe~ ~ grate Pl~n~en~ overl~p each othe~ oof tiles~ the ~te element~must haYe air escape or~fices in order to be able ~o fe~d ttlÇ pl'il~lary combustion ai~ from
below ~ grate flool~ which aze ~onstruc~ed gf individu31 air~ooled grate bars, the air escape
o~ifices are forme~ either at the head ends of the individu~l ~rate ~ars, or on the fl~nks of
~eighboring ~rate ba~s. ~7ith this conflgLIration1 especially ill waste incine~ n p]ants, h~d
p~rticles of cinter or small pieces of ~netal scrap can pelletrate into these a.ir escape orifi~es,
and ~is effect is fuIther intensified by the stolcing movement of ~he gr~ting ~,tages. Molten
non-fesTous metals or bitumen-like subst~n~s can ~Iso penetrate into these air escap~
orifice~! impa~ring the even flow of air to the n~ateriaJ to be burned~
To counter the danger of ~ueh a~r escape ~fi~e~ becoming plu~ged, Gcnnan Patent
41 05 330 Cl ~iscloses a grate ba~ which has ;It the he~d end of the air-c~oled grate bar ~n
M~ 17. 39i1 ?: ~,'?h{ ~01~ hERRCI~A~02yAo~l'725 1997-06-03 NC~ r P. i/'
air esca~e onfic~e which is directed obliquely downwa~d and which expands uuL~ . In the
~se of another dicelosed air-cooled grate ba~ in accordance wi~h ~ermarl P~ten~
42 0~ 502 C ~ ~he back of the grate bar at the head end is ex~e~ded and aIlgled ~wnward
o~er the face of the end of the gr~te ~ so that the b~ck of the ~r~te bar~ ~fhich is pulled
downwa~d, fonns a lip overlapping the fac~ en~, which ~ip lilI~ts the air escape orifice,
whose outflow emerges pal~llel to the face of the head en~ oth kno~n implementations
reduce the p~oblerns explaiTIed above, bilt fail to elïmin~te ~hem completely.
The object o~ the present inventlon is to ~reate a grate eIement and a gs~te for combustion
plarles w~ich elimin~t~$ the daII~er of ~ s~oppage of the air passage an~ r~kes cleaning the
air passa~e simple.
Under this invent.ion, this problem is solved on the ~asis of a grate element of the type
d~sctihed at the be~inning7 by the fact that the a~r ~utlet for ~he primary combustion ~ir is on
the bottom si~ of the gr~te element head, open~n~ downw~rd, and that there is a leas~ one
fixed cleaDing proJe~tion on the top of each ~rate element ~or the air outlet of ~e ~rate
elelnent which lies a~ove it in the ~ssembled state.
Config~ring the aif otlllet on the underside of the gr~te slement head is an especially
favo~a~le means of providing ~ w~y f~r blowiTl~ cut light and s~ll particles which t~ave
entered ~e ai~ outlet, and fu3 Li-~nx~ore thc cl~nlng projection or projections n~c~ bnng
abollt a clcaning of the air oudet, even in ~he c~se of s~ongly wedged cinder particles or eYen
mol~n ma~,ses. This ensures the a~roi~ance of incomplete combustion processes OFo~rh~in~ and conseqLIent dam~ge to g~a~e elernPl~tc~ whiçh lead to ~el~ively long penods
of down time for the repla~eluent of such damaged gr~te elements. Since the air outlet on the
undelside cf each grate element opens downw~rd7 the res~c~ing ~all v~ the ai~ outlet, which
is formed by the grate elemP~tr which lies beneath it in a~ ~csemb1A~I finng ~rase, is in
m~tion relative to dle upper hmit~ng w~ll a~,si~ned to the grate element d~r~ng ev~ry stolcing
strol~e, so that tb.is relative n~otion itself b~ings ~bout a good c~ g of solid p~ticles from
the air flow path.
An addition~l advantageous extension of the invention consiSts in posi~ioning the ele~ninE
projection or proj~ctions in the rear area which faces the ~ n~ or driYe end ~f the ~rate
MA . . 7 ~ ~ g ~ ?~ r~ EF~ A~'~02~o~Ts72~i 1 997 - 06 - 03 NCi 8 rl 6 P.
el~ n~ By tllis means! reg~rdless o~ whetlle~ tlle gra~e elem~nt belongs to a fixcd ~a~in~
sta~e or a nlo~ing g~tin~ stage,7 the c1~nin~ process takes place by means of eYen~ cleaning
projection duling an ope~ting phase in which p~shin~ pressure is relieve~ ~t th~ f~e of the
~rate element head, between the gr~te element head and the matenai t~ be bu~ned in front of
it. This prevents additio~ terial to bc bu~ned from being pressed throu~h the air olltlet
~y the rcla~ive mo~.~ement between the ~leaning proje&tion ~nd d~e grate çlernent, which
would increase the quantity wh~ch fall~ throu~h ~e g~ate. ~ this configuration in ~cordance
with the mvention, the cl~aning projection or p~ojections are alwa~ts pushed into ~e a~r outlet
when ~e col,~syonding grate elements move ~g ~eir position of gTeatest distance from ea~h
other, i.e. ~fhen the ~rate elen~ent head of ~e above, driven grate element rno~es lowa~d ~he
re~r ~n~h~ent or drive end of the lower, fixed grate element, or the gr~te elen~en; he~d of
~e lo~ver, dr~ven gr~te eiement move3 forward a~ainst the aboYe, fixed grate element fr~m
thç latte~'s grate element head.
~n e~p~ej~lly 3dvantagecu~ n~riv~ of the mvention is distin~ chpd by the fact that
ev~y cleaning projecdon has a tongue-like sh~pe arld every end which enters into the air
outlet is tapered. The tapering of the end of the cleaning projection or pro~eetions which
enterS into the a~r outlet exerciseS ~ wedge effeçt on the jamm~d particles, which makes the
cleaning easier.
The cro~s-sectional shape of a cle~nin~ p~ojeçtiull does not n~cess~rily need to be adapted
to the cross-s~tional shape of the a~r outlçt, cspecially not if possi'Ple blo~kage~ of the air
outiet ¢onsist p;~n~rily of solid particlee" ~inc~ t~e re]ative ,rlovement of the one IiTnitin~
wall d~scribed e~lier, in coLnbinaticn with hi~h o~ifice velocities? ~ ke it po~sible to
achieve a good cleaning effect. But if molten masses in doughy condition are to be expected
it is advisable for the çle~-ing projection or projections to be ad~pted to the cross seçtio n of
the air outlet, except for ~ requisi~e freedom of play. Such an e~tension is ~dvanta~eous,
es~peci~lly in c~Lnhin~tion with the con~lgur~ion of th~ elearling projeetion with tapere~ e~d
d~scrihe~i fu~ther a'oove, since the tapered elld creates an ~d to insertion, because late~al play
of a grate element cannot be enti;~ly preven~d.
If, in a further ~xtension of the inYention, the supportin~ and gui~ing surfaee of Ehe grAte
ele~nen~ has an ~vetlay consisting of wear~re.e,istant m~te ial, this avoids consl~iction of the
T.~ 4 y ~ ~ ; ,. 9 ~ ~: ' 3 P1~ E P - CA1~ o 2 2 0 6 7 2 5 19 97 - 0 6 0 3 N3. 1 ~ I ~ p ~ 4
3ir outlet due to wear, which prolon s the u~ful life of s~ch gra~e elemen~s. Re~q~l~e without
such a wea~-resistant overl~y the grate element w~uld drop ~o~n beca~se of wea~, which
w~uld make tbe air ou~let on the bottom side smaller.
To colTect sucit ~ear-related constriction of the air o~tlet, re~a~dle~s o~ whether or not the
g~ element has a wear-resistant overlay, e~h ¢le~nin~,. proj~ti~n carl have ~n aggres~i~ely
ab~asive surf~e, so that with increasin~ wçaring of the ~up~ort and ~uide surfase of ~e gr~te
element t~e air outlet is ground f~ee by the abra~ive surfaee of the cleaning pr~jee~on.
~he air outlet can take different fo~ firs~ ~n-bodil~lei,t, the air ~utlet ~an extend ~oss
~~e entire wi~th of the ~rate element. As will be expl~ned in greater d~ail in ~s~-n~lion with
a ,~ designe~ in ~~ordance with the invention, s~h a con~ r~ion ~quires ~ itional
~uide for e~h grate element, Since in ~his emb~ment the head ~rea Qf the ~ratc ~Icment
cannot ~ie on the grate elemerit beneath. According tO ~ different cm~odiment under the
invention, the ai~ outlet can e~ctend over ~e rem~ining rvidth of the ~r~e elemerltt except for
two la~e~l ridges whieh serve ~s ~ui~es an~ SU~)pOIt5. Itl this configuration the additional
guide c~ be dispensed wi~ ince the rit~es which are left in ~hc are~ of the flanks can res~
on the ~ra.~e elemerlt '~eneath. In a prefeffld embodiment, the air outlet cons;s~s of sever~1 air
orifices ~hich are separ~ted from eac!~ od3el b~ ridges. ID this sort of ernbo~iment i~ is
ad~ ta~eous eo ~ave cle-~nirl~ projec~ions on the top of each gr~te element colTespondin~
to ~tle num'oer of do~nward-openin,~ ~ir orificcs. This ens~res th~t all of the air oriflces,
which in the aggreg~e .eons~ilu~ the air ou.~let, can be cleaned by correspondi~g cleaning
projections.
A grate fo~r eombustion plants, havin~g gra~ing stages which 1ie in long~tu~inal rows in the
direction in which the m~eAal to be ~urned is fed, overla~p~ng e~h other like roof tiles an~
alternatin~ between mov~ble a~d stationary ~r~tin~ s~gesl c~nstruçeed of indi- idual grate
e1ernen~s which extend ~r~s the entire width of the ~te or of nnul$Aple grate ~1. ~e~t~ Iying
adjacent to ea~h other in accor~anee wi~ on~ of the c1airns I th~ough 10, is ch~ct~ cd by
a support ~ g~ nt ~ on the grate elemen~ h~ad (7) on the station~ry gr~te element ~2)~
and a guid:n~ arr~ngemcnt ,~or each ~r~te element, which hold the underside of the grate
element ~ead at ~ distance above lhe und~rlying grate elemen77 to form an air outlet
c,c ~ ross the entire width of the ~ate element. Hence ~he ai~ outlet i~ formed by the
9S7 L:~-'?l~ ~1'03r~ EER~'~CA~0~2~2-~01~2~ 1997-06-03 Nv .37~ P. 7/~
fact that the ullderside of t~e grate element head of the g~ate ele~ t whi~h is Iying on top
in each case does not li~ direetly on top of the grate ~ cr,L ben~atll, but is held at a sligh~
d~ n~e from the gr~te element beneath by the guide a--Ar.~ t~ eoi.~onding to the~lesired air p~ssage cross section.
~ there are ridges in t~e a~ea of the air outlet, either in the e~ge areas of the ~ate element
or dis~ibuted over the width of 211e grate element, then the ~idges v,rhich are loc~ed in the
outlet area c~n serve advantageously as a support a~d ~uide amngement for each gr~te
element on the ~rate eloment beneath.
In an additional advantageous configuration of the invention, if ~he cleanin~ proJections are
Iocated within the air outlet at the stroke reversal state~ closing it to a sukst~tlti~l degr~e, this
creates a brief a~r bloc~R~e, which 1eads to a mo~e vigorous bl4wing out of the loasened
pa~iclos ~hen the air outle~ is subsçquent~y clea~ed.
To pre~en;t fluid parti~les from slipping or flowing intO the a~r outlet ~t the stroke reve~sal
state, in ~n additional ~nfiguration of the in~,entio~ the clePning p~ojection or projecdons
c~ protrude slightly o~er the he~d end~ of ~he grate elcments at the stroke reversal state.
However, it is often sufficien- for ~he cle~ning proJection o~ prOjectionS to merel~ stop flu,sh
with the head ~f the ~ e element in th~ ~troke roversal position.
A procedure for OyC~ g a ~ate in acco~dance wi~h one of the claims 11 to 15, with
st~ble str~ke length for ~e ~vable g~te elem~ntc, iS cha~a~terized by ~he fact ~at after
an optional number of stoking strokes the system is set to produce a lon~er cleAnin~ stroke,
where the cle~ninE p~o3ection or projections will en~er the ~ir outlet. It is advant~geo~s in this
case to jet a cleani~g stroke deperldent upon the air ~l~S~UL~ wlli~h exis~s undemeath the
grate elernent ~;vhieh is to ~e re~lated, andl~r upon the ve]oci~ of the p~mary air in this
area.
The invention will be desuibed in ~reatel detail in the follo~Ying seetion~ on the basis of a
number of sample em~ m~ illust:rated in the drawin~. ~he drawing shows the following,
Figure l; a ~raphi~al representation of a first version of gra~e elen~ents which
MAY ~ 91 ~ ?M '~I~OD E~R~A~0~2~2~0~72~ 1997-06-03 N~ 876 P. 8/~4
are o~erlapped like ro4f tiles; and
Fi~ur~s 2 to 4: ~ddition~l ve~sions of g~te e~eln~r~
As may be seen from~Figure 1, a ~ate for a cQrnhu$tion pl~nt is cons~ucted of a number ~f
g~ate el~rn~ntc 1 and ~ which overlap c~ch other like r~of ~ilcs; the grace cleme~s I can be
~oved ba~k and forth in the direçtion of a~ows 12 and 13, and the grate elen~en~s 2 are ~Ixed
in position. The grate elements 1 ~rG ~cif~n~d to a drive n~echanism 4, whi~h e_.lcr~.L~s the
requisite s~oke for t~e necessa~y stoking movement. The length of stroke and dle s~ohng
speed are adjustable, this, a~on~ with a var~e~r of other influenring factors, make it possible
~o influence the combustion process on tlle grate. Every ~ e elem~nt, in~rp~.n~l~nt of how
it is constmcted, has an o~t ~rhm~nt or dnve end 5 whlch is hwked into a holder 67 where this
holde~ is ~Irrnly conl~ec~d to the drive device 1 in ~he c~se of the driven gr~te elements.
addition, each gr~te elements has a head end 7, a foot 8 and a back ~.
On ~e foot 8 of the grate elemem the~e are a number of recesses 10 ~4hich open downward,
which se~e as air escape orifices for the prima~r air, which is fed from below. These air
escape orificcs constihlte the a~r outlet.
On the back 9 of each grate element, preferably in the re~r area which faces the ~tr~ m~nt
or d~ive e~d S, th0re a~e e]e~-lin~ projections 11 in fixed position' their nu~nber corresponds
to ~e nurnber of air escape orifices 10 'rhe cross sec~onal shape of ea~h cle~nin~ proj~ctiorl
11 is ~apted to the cross se~ir n~l shape of ~he air escape onfice 10, except for requisite free
p~ay, al~d the cleaning projections 11 are located within ~e attainable stroke ran~e o~ the
overlying grate element. rn tbis way, wi~ each cleaning push the cleaning proje~tions 11
,r- ~t- -~' into the a~r es~pe orifices 10 ~etween swo c~rrespondin~ gr~te elements I ~nd 2,
and in so doing d~ey remov~ ~e solid particles or molten mas~es which have entered there.
~lle cle~ning pr~jections can have tapered ends, ~o make ~t e~sier to introduce them into the
air escape orifices lû and to exercise a cercain wedge effect on the p~ticles which are
~ammed chere.
The tenn cle~~lin~ st~oke is used for the ]ongest stroke which can b~ set with the dr~ve
l, r~h ~ . jS7T1 4 ~ependin~ upon how much risk there is o~ blockage of the air outlet ~o~med
9 1 G 4 P I~l ';! 5 t' 3 ~; ~ R F~ ~ cA~ 0 2 2 0 6 7 2 j 1 9 9 7 - 0 6 - 0 3 ~ I~ ! 8 ? û P ~ / L 4
by the air ex~t onfices 10, cleanin~ strokes can be set with the app,o~l;ate frequency. The
co~r~s~onding adjustment pro~edures a~e carried out in ~ccordance with the air pressure
andfor air Yelocity which prevail ~ the area ~e~eath the grate element which is ta be
regulated.
the cl~nin~ p~ojec~ions are loc2ted in the rear ~rea of each g~ate element, an~ sti]l within
the ~le~ni~ stroke, then the ~ir escape orifices 10, for exampJe in the overlying station~y
gr~te elenllent 2~ are clea~ed at the end of the fon~ ~ovement in the direction of arro~
by the cle~ni n~ p~oJ~ctions I I which are positioned on the mo~ing grate elcment 1. However,
in this phase of the moYement. because of the folward moY~men~ of the grate eleme~t 1,
there is no pushing force p~e~ent at the g~e element head 7 of the overlyin~ stauonary grate
element 2. The air esc~pe orifices 10 of the movable ~rate element 1, in contrast, are
p~netlalcd by the eleaning projections 11 of the underlying stationa~y gra~e element at the
end of the baclcward clci~ r strvke, whose direction of mo~ement is in~ic~te~ ~y arrow 13.
~)ue ~o this bacl~ward movement there is also no pushing force p~esent ~t the grate elen~ent
head 7 of ~e moving ~ate elemellt 1, whi~h pre~rents solid palticle~ from being pushed into
the air escape orif~ces 10 b~ the cl~nin~ projections 11~ The ~le~ning projections 1 I can also
be positioned at other locations~ however, so long as c~re is t~ken to ensure that ~ey c~n
~net.~te into the a~r escape onfices 10 ~ r them ~ithin the ~t~in~hlG 3troke ra~ge.
The ridges 3 which rem~n in the m~ginal area ~nd b~..~n the air esc~pe orifices 10, which
are in ~e foTm of downw~d-openlng recesses. serv~ as ~ support ~nd ~uide alTan~ement,
aIld rest on the respective grate back g of ~he underlying gra~e elem~ni
To avoid excessive ~rasion of the nd~es 3 on the foot ~ of the ~rate element~ whieh would
le~d to a redu~tion in size of th~ ai~ escape orifice~s~ each ridge 3 ~an be equipped with a
wea~-resist~llt overl~y 14~ In the absen~e of cuc~ an abrasion-tesi~tant ~verlay 141 e~ch
~e~nin~ p~oje~tion 1 I c~n have ~ abrasive suIf~ce 15 on its top~ ~o that wi~h e~h cleaning
stroke the upper edges of the ai~ esc~pe ori~ 10 are ground oK to collespond to the wea~
on the ~idges 3, so that for a certain operating pe~iod this re-~nding of Ihe ~ir escape onfices
10 makes it possible to corl~nue oper~tion of the grate elements despite the ~ear w~ich h~s
U~ , since the reduc~ion in size of the air escape orifioes whicll ~sually occu~s due to the
wea~ on the foot of the grate element ~r on lhe r~dges ~ is canceled by this ~nding effect.
