Note: Descriptions are shown in the official language in which they were submitted.
49-~lt,l-6~ 6 l~uh~e~ c k~r ~I. Pa~ . '313g P0~ 23. 11~ 44
'Z~ L39~
P~oce~ for ~an~fa~turin~ ce~t compon~nts ~ith l~te4r~11y
cast~ at le~t app~axim~tely ga~-tight high-tornpe~ature
in~ul~ti~n
The pres~nt invention re~etes to e proce ~ ~o~ ma~ufact~rin~
c~st ~omponbnts w~th int~yrally e~t hlgh-teinperature
insulation which is ga~tio~ht by Yirtue 0~ 9 ~le~ c ca~
or hlgh-t~mperatur~ ln~ul~tion ~hich hin~er~ ths pa~g~
ga~ in a~cordan~ with the g~neric part o~ clai~ 1.
Work haa bee~ in progrr8s fer ~ome tlme to prov~d~
p~rticular~y ~a~-bo~ing component~ of lnt~rn~l co~buotion
eng~nos 6uuh ~8 tha combu~tion ohAmbor, th~ preaombustlon
cha~be~ l chamber, piston trough~ sxh~ust/lnlet port~,
exh3u3t m~nifold~ pipea, turboch~g~r or gas turbine hou~ing,
with a hlgh-temperet~re Shorm~l in~latio~, as e~ nc~d by
Ge~man patant appllcation~ 3~ ~3 591, 34 11 ~35, 34 46 649 ~r
35 21 467~ Such a th~rmal in8ulation p~r~it8 the eff~ie~cy
~r power ~enalty of int~rnal oo~b~stion ~ngine~ to ~
ln~rea~ed ~nd their Hnvlr~nment~l pollution to be r~tUced.
For ex~mple, the u~e o~ hi~her tsmpera~ure3 ln th~ exhau0t
8yc~em of ~n intern~l cambu~tian Qngine enco~r~es a
reducti~n ln the disoh~gc of carb~n ~onoxldo beoBUa~
mo~e ea~ily oorlv~rtod to ~r~on d~xld~ ~xhau~t ~a~
~crub~ing con ~l180 advantaqRuu~ly be carrlcd out ~t high6r
temper~turo~.
In thi6 ro~ard it woul~ thsoretL~ally b~ ~oirabl~ to ~tt~pt
to ~xacut~ all gas-besrlng w~lla in ~ ~uitably hYat-r~el~t~nt
thormal i~sulat~on m~t~rlsl in prsotiee, h~wevo~, th$s i~,
of aour~ nut posalble in vi~w oF tho prea6ure~ obt~lning und
~th~r mechanicel ~ltr~89e~3 ~ with tha result that the g~-
b~r~ng aomponent in pr~ctico requ~o~ the support of a loAd-
b~r~ng ~etallic Component, mo~tly e castlng whlch, ~or
~g-~ælt,l-~ J~396 3æ'3 F~-~3 ~ 9 0~:45
~ea~on~ of the~n~al technoLog~ ~ iQ ~v~nt~geou~ly mo~ntl~d on
th~ ~u~sid~ ~f th~ wall o~ th~ ga~-b~rin~ c~nnp~n~nt.
A hish-tsmpe~a~re ir)~ulation sy~ten~ parttcul~rl~ for
roeiproo~ting-pl~ton interrlal co-~b~tion englnea known ~s
ISOLITE is knawn in tho art fro~ pu~llsh~ produ~t litbr~tur~
of G ~1~ Mont~go GmbH .~n whiCh an in~ul~tlng bady is
pr0fnbrioated ~f ce~mic ~lbro~ con~sting of Al203/5~2 ~la~
on bath ~ido~ ~ith C thin otsinlo~ st~1 she~t and then
onclo3ad in h met~l ca iting. Th~ inn~r sto~l oho~t oladdls~q
function~ metalllc ~u~de ch~nnel ~or ths hot ~a~os~
whil~ ths o~er ste~l she3t ola~in~ pr9vent~ mnlt3n mq~3
penetrating the lnaul~tlng ~at2r~1 dl~rlng tho o~ting
procv~. In thi~ ~oy an into~ral oolllpo~l~nt i3 creatod with
load-boaring C~19t wall Pg tho extern~l layor flnd o high-
t~persturc thermcl ins~latinn ~Hyer c4nrlect~d direotly to
thi~ with a amooth ste~l delinoation ~f the i''lo~ ~p~ce.
Tho ea~ting Of ~uch A componentS how~ver~ i~ not ~ithout
d~fficult~- A~ a rule~ th9 end flan5cs of t~be-~h~pod
componsnt8, e.g. an ~xhau9t m~nifold~ are m~chine~flni~hod
which ~o~ns th~t the hlgh-tempcratur~ inaul8tlon m~st
termlnete b~r~ tho axial ~r~d of the oompsnent. ~hus ~ring
ca~tin; the high-temp~atur~ lnsulatlon mù~t ~e hold ~n oc~es
~hi~h ~o a~lh~2~tad to molt~n m~ in the ~xlel viclnlt~ ~f
the high-tempor~tur~ in~ul~tion. Thig ~e~u~t~ in problem~ in
c~nneo~icn with ol~an ~ntrin~ ~o th~t the wflll ~hickno~ ~f
tho c~tlng Q~nnot be l~a8 th~n a quit~ sub~tan~iaS v81ue~
In addltion~ the hard cores most be removed ~rom the inno~
space o~ tho ~4a-conv~ying channel ~fter tho castlng pr~c~
which 18 costly and csn Hl~O r~sult in damage t~ the s~Qth
surf~ce of ~h~ inn~r ~tool 3heet claddln~ by th~ ~o~e ~fl~,
Fu:rtherm~rr~ i~ is ~i~ficult to ~void mcltnn mo~a flo~ng
alDng the ~ 'qce of the r~t~ining core~ t~ tha lnside of ths
steel sheet oladding.
~3~ t~ "~ .3c~ l.F~ 3 ~ ~ g~9F~ 2'~ æ:4r,
~y c~ntraet, it is the o~ject of the lnve~inn to create
proc~ to manufacturo ~u~h c~ti~9s proYlded with high-
~empcrat~ in~ulatio~ as are ~it~bl~ fo~ e~flcient, ~law-
frea ~nd d~f~ct fre3 m~ss produ~tlon w~th a p~fe~tly u~F~
~nd ~ all thick~e~q ~f thb ea~ting.
Thi~ obJ~c~ i6 ac~ ved by m~an~ of tl e ~hara~ter~stic
foatures o~ claim 1.
Ths u~e of tha full-mou~d castlng process for thto
app~lcati~n makes it po~sible to elim~n~te t~e dis~dYant~es
descrlbed above. ~he exp~ndod plaYtic shapeo c~n ~e ma~s
p~o~oed ~ff10iently in appropriate ~xp~ns~on moul~3 - ln
similar ~eohion to injectlon-moulded g~od~. In shapo th~y
correspsn~ complotel~ to tho l~ter cn~ting ond alre~dy
contain the high-t~mporature ln vlstion~ Then the co~ponent~
pr~febrlcat2t L~ this w8y wlth the U~e of expand0d pIa~tic~
simp~y need to be pl~ed in ~n approprl~tely f~uidi~ed mould
medium ~uch a~ cand or the llke and, a~t-r ccn~olidstlon o~
~h~ sand, f3r cx~mpl~ ~y n~ns of vaculum pr~Yore, c~t
during ~hieh the molt~n m~ ga~ifie~ th~ expanded pl~tic
~nd takes it3 placc . Sinc~, in ~he full-mould c~ting
proceos, the molten ma~3 ~utomati~ally occup~e~ the ex~et
spaco occup~ed proYla~ly by tho exponded plaati~ th~
dTfficulti~ Ysoci~t~d with ~izing, pooitional at~billty~
coal~ etc. ca~ bo t~nof~ d to th~ st~9~ ~t whîch the
expand~d pla~tic model i~ m~nu~ctured wher~, by ~ontrast
with th~ pro~e~ u~lr g molten ma8s~ ~u~h problems ar~ 909ily
d~lt w~th~
E~p6ndcd pl~tic ~odel~ for full-mould castlng ~re ~u~lly
manufactured by 1ntroducing expandablc plawtlc yr~nules ~nto
a mould c~vity whoee width corre~pon~ to tho wall thi~kn~ss
of the ca~tlng and are ~xpand~ the~e by intro~uclng a hoe~
tr~n6f ~r medium ~uch a~ ~uperheated ~t~snl~ The inlet ~o~ th~
.
~i4-n~lt~1-6~r36 l~uhnen,l~J~ck~r u.P.~ ~ag P05 23.10.~ 8:47
--4--
s~p~rhea~d st~am or tho lik~ i5 l~ated on ono of the l~ge
~urfac~ of th~ w~ll, and the steam 1~ extrs~ted ~n th~
opposit~ ~all aft~r pasoin~ through the g~onules. rhe
sho~tno~s of the ~te~m t~vel thr~u~h the ~ranu ~ e3 gueranteoa
th~t thc st~m ztill retains enough th~mal Bner9~ evan at
it8 outlet pol~t, i~e. 1~ still aufficio~tly "unused" t~
guarantee c~plete expsn~ion ther~ . At~nt.i~n may be
d~own wi~h ~egard to these conditi~ns to Ge~an patent
appllcati~n~ 5~ 47 6~5 and 33 47 616, to th~ ~ull cont~nt3 of
wh~ch rsf~ren~o is made.
HoweYe~, ~uch a procedu~o ~or manufactu~ing exp~nded pls~tic
mod~l3 i~ not pasalbl0 fo* tho ~a~tings which ~re to b~ m~de
in th~s case s~nc~ steam o~nnot pa80 through the hlg~.
t~m~oraturo lho~latio~. ~t best, thereforet the ~t~am ~an bo
dr~wn Pl~n~ the high-temperature lnaulatio~ ontc the OPpC5~te
side of ~h~ ~odel and th~n ~xtract~d there, Sinc~ the
met~llic ws~l~ of the exp~nsinn mould ~r~ maintai~ed st ~
~on~ido~obl~ lower temp~r~ture th~n the ~te~n in ordo~ to
avoid p~rtl~l premstur~ ~xpan-~ion of tho plastio g~anulas
du~lng ~h~ fllling prqoess and slnce eno~gy contlnue~ to be
extra~ted from ths ste~m to h~nt the plsstic gF~nules t~ the
e~p4r\310n tomperature it .i~ not gon~r~lly feasl~le to ~oute
st~am psrellel to the l~rge a~e~ e~ 8 ~oll if complet~ and
ssturated ~xpanslor~ ~e to bo achloved Qt tl~e ~toam outlct
which i~ located rar ~rc~ thc lnlet~ tt i5 e~ential ~
how~ver, thst suoh cxpanaicn bo ~ohioved in order to produce
~3sting with a flsw-f~ u~f3ce.
Thi~ diffloulty ~loc ccnnot bo o~orcorqe by introduclng th~
stoom ov-~ e prolonged period 80 that as a r~ult ~ t~o
rresponding heating of the 0xp~nsion mould walls the h~t
~,oeo o~ tho ~ ly introduced ~team i~ oontinuously reduced
untll rlnslly ste~m ~t the decirsd temp~rature i~ ailable
in ~ho oxtraotion zone. Thi~ i~ beoause comPl~to oxp~n~lon
J~ 6~ 9~ u. P.~r . ~3 Pl~6 ~3. 1~ 39 08: ~
5:~396
~f th~ pla~tic gr~nule~ ln th~ ~teon~ inlo~ impede~ the
~t~m f ~ ~w s~oh ~hat o~ly a l~.mited volume Of ste~rn m9y b~
~ntrodu~ed. The heat ~bntent o~ tl'tis lnjection of stenrn ~uet
then ~uffio~ for ~he compl~t~ e~p~nsion ~f the pla~tic
gr~nul e~ .
Surp~isingly, hcw~vor ~ it ha~ bn~n 9hnwn ~hRt ~lthough on the
on~ hand ~h~ higk~.tRmper~ture infiulation af tho ~st~n~s
~nufsctu~d ac~ding to the p~ent inYent~an p~o~ents the
p~usage ~f o~eam thr~ugh the w~11 in ~h~ usu~l ~annsr ~ a
r~ult of ~8 inSUffiOi!gllt 9~1S p~rn)e~bitlty~ On t~ oth~r
h~nc becauso of ite therm~l ln~ulatlon ~fFect 1~
s~ stnnti~lly rcdu~ee ths heet loe~ of the 3toom during ita
l~ngthy p~t~ ~long the p~riphery of th~ h~at ln~ulat~on
mat~ri~l, a& a ~asult of whish it c~n a~ver ~ ~n~id~rably
greatar distanco in th~ expan~ion nlo~ld be~ore it i~ us~d ~Jp
and un~bl~ to c~use oan~pl~to oxpansi~n.
The meeeure pravided ~or in cl~im 2 en~urea ~h~t the haat
105s of the steam an tl~ sldo af the exp~nslQn moul~ ~-ppositv
tho hlgh-t~nlpr~atu}~ in~ul~tion io aloo minimised~ altho~qh
thi~ h~ 109~ red~ctlon is limite~ ~y th~ maxî~u~
ternper~ture of th~ expanaiort mould ~all whlch ie less than
tho ~xp~r~sion t~mp~r~t~r~ of tho plaoti~ gr~nule~ ~nd is thUB
su~t0nti~11y below the 3teenl temperet~re~
Furth~r det~ils, ~e~ture~ end advant~o~ of ths InYontian ~re
cunt~ined in the fallowlns description of one embadlm~nt wi~,h
th~ ald of the acq~mpanyi~ dr~in~s in which:
Fig. 1 ~ho~s a ~oction thr~ugh ~ ca~ti~g ma~nuf~tu~ad lr
~ccordan~ ~ith th~ invont~on
fig~ Z a secti~n thro~h the expon~ion ~oul~ perpendi~ular
to the ~xl~ of tho c~eting.
4~ t~ !q~ . P~r. g~ Pl~17 -'3. 1~ 9 ~ 4~
396
~6--
In ~ig. 1, for ~x~ple, a ca jtin~ manufa~tured ln accordance
the ~o~c~o of tho inventi ~n in tho farm ~ n u~te g~
duct i3 111UBtrated~ In i'c, tho cast iron sl~ev~ of the
~Y~Sto 9~ d~t i~ d~i gnated 1, and ~ ln~loat~o a high-
tempe~a~ure ~n~ulation whi~h b~gins a short di~tanc~ f ~om
connecting ~lang~s 3 ~nd 4 o~ ~thoF ~urface~ o~ th~ castlng
wh~ ~h h~v~ ~o ~ f iniohed ~u~h a~ the thro~d S ~hown and
osY~r~ tho whele of th~ inner periphory of ~he c~stin~. Th~
hi~3h-tomperature insL~l~tion 2 consi~ta of an in~ulsting bady
6 ma~ of ~ufficien~ly he~t~esi~t~nt mn~1 or c~r~mi~
fibros covered on both sides by thin st~inle~e ~eo~l ohe~t~
~oils 7 #nd 8. tho purpose o~ the inno~ sta~nl~6s ~to~l
~h~t ~oy~ 7 is t~ provide ~ smo~th sur~ace ~hlch is
r~lot~nt t~ ~ea~ c3uaed by the ga~ fl~w~ Th3 end~ o~ the
innnr ~tainlesa ~teel ~h~ot 7 aro ben~ ov~ to form tong~e~ 9
~hich pr~ ject intO~ the moterial ~ th~ cqstin~T thls fi~in~
of th~ tongues 9 i8 ~chl~ved ~mply in th~t th~ molten ~
of the ca3ting m~terl~l flows ~ound the tonsu~9 9 during the
tln~ proces~ and s~lidifies there.
The stsinle~s ~to~l ~heet 8 t~rminat~ b~fore the tang~e~ 9
of sta~nless ~o~l ~hoot 7 and ~ov~r~ th~ insulating body 6
to p~ot~ct it from the ~olten ~a68 during c~tlng. The
stalnlco~ ~t~ heet ~ is h~t visibl~ in the flni~h~d
prad~Pt .
A~ lc plsin to D~ ~ the high-te~pe~tur~ insUlAtiOn 2 mu~t bs
loo~tsd lnrldo q ~otin~ m~lld and ourrounded by th~ molten
ln a~der to m~nuFscture su~h ~ cnating. The rlo~ paths
mu-t, howev~r, b~ kept ~ree of moltcn m~s3 ~nt, if a
unitormly thin w~ll thickn~ss is to be attRlned~ th~ hi~h-
tempe~st~re insul~ n ~ust be p~ition~d v~ry ~ouratQly ~n
the c~tîng ~ould .
T~TO~ b a~
~'3 -1~ b ~ b ~ I, F .~ I ?~,'3 F~ 3 . 8? 1;~;3, 4 3
396
--7--
In th~ f~ nould ~antin3 pro~ss wh~ u~e i8 provi~od for
in th~ invF-n'c~on, t.ha ta31~ of ~ccur4te pos~t~oning of the
high~emper~ture in~ula~lon 2 is tr~nsf~rr~d 'co th~
production p~oc~s ~or ~nu~acturlng th~ expandRd p~,astic
mod~, 1 .e. the high. t~perstur~ ulation 2 is flrgtly
surr~unded by ~xp~nded pl~tic ~t~rial which c8n be qa~ified
and corr~pond~ exnctly to the shape o~ the ~astlng; th~
~atorial i~ then ge~itled when the ~olt~n m~ss i~ poure~ in
and replac~ by the molt~rl ma~c. PArt of such ~n ~xpan~lan
mo~Jld ls shown in Fig, z,
As oan ~o s~en from this, the ~lcw psth o~ th9 latsr casting
is surrou~ded by thq high-te~p~raturfl lnsulatlon 2 wlth ~he
ln~ulating bod~ 6 and the atair~ s steel sh~ts 7 ~nd 8 on
both si~o~. A wall ltl of an ~panslsn m~uld de~lgnltod in
its entirety by 11 i8 loceted ~t a given distanoe ~ro~ th~
auter ~tainle~ ste~l shoot a and f~rrn~ ~n opening 12 which
corraaponds ox3ctly to tha wall thloknes~ ~f the metal in th
later ~ting. Expsnd~ble plastic granul~8 13 arc insertad
into tho opening 12, a~ is al~eady known 1~ the art in
relation ~ full-mould casting, and ~hen ex~nded ~o tha~ a
model ~0 formod in whlch the ga~ifiable expa~ded pla3tic ~o~y
i~ in the exaCt po~it~on o~ ~he ~et~1 in th~ later ca~ting.
Thc uxpsnsion of th~ pla~tl~ grQnu~s 13 ls aoh~vQd ~y
p~sing ~ heat trnn~fer ~dium, gan~rally ~upHrheated steQm~
th~ough them. Th0 6tcam iY int~oduced lnto ~ho granulos 13
t~rou~h st~am nozzlcs 14 and ex~racted through approp~late
norzle~ cn th~ inner periphery ~ the op~nlng 12 during thg
prnductL~n of st~ndsrd model~, In ~h~ way, tho ~team pass~8
trangver~oly thr~uqh th~ wall of the model, tho~b~ c~Y~rin9
a minimum dlstanc~ ln ~he plo~tic ~ran~les 13. Thi~ 13
lmportnnt boe~e ~he ~tea~ l~s~s cn~r9y durlng it~ p~age
thro~gh the pla~tic ~ranule~ 13, ~n~ thi~ energy loss ~uot b8
kept to ~ minimum ln crder far complete and uni~n~m ~pan~ofl
,161-~ ?~ al:let ll.F~ ?~ P~1~ 2~.10.~g ~8:4'~
X~ 9~
of th~ plastl~ gr~nule~ 13 ~ occur. If? howeY~r~ th~ st~
ha~ t~ ~over ~ longs~ diatsnce in the pla~tic g~nu~s ~ 'che
3n~rgy loss qu~ckly beco~e~ ao high that c~mplet~ exp~nsion
in the ~eam outl~ zcne c~n no longer b~ ~uar~nteed. It
s~ould be noted tha~ th~ steam inlet ls increasiffgly impedod
esUlt, o~ th~ ~xpan~ion pI~oc~6~ o~curri~g thers beC~u~e
th~ inter~p~es b~otween ~he granale~ ar3 redue~d ~urino
~xponsio~ clr~d fln~lly di~appe~ complot~ly~ with the rl~8ult
that o high raeiYtance to the eteem fl~w quickly buildg up.
lt i~ ~elf-e~ldant that tran3~r~e ~low of th~ pla tlc
granulo~ 13 ln the opertlng 12 is not pos~ble if th~ in~er
sllrfac~ of tho ~pening 12 is ~ovor~d ~uch thst it le
e~entl~lly ~o~tight, ~Uch a~ i8 th~ ca6e h~re be~u~e Of
ths ~tslnles~ steel ~h~et 8. In p~ace of th~ ~tainle5s ste~l
~hee~ 8 i~ wo~ld alQo be pos~ible to u~o a ccrami~-based
bl8cking sueh as zircon oxi~o althou9h il; w~uld be es~ent~el
for this to b~ diffusion-proo~ to prevent ~tearn p~notrating
~h~ i~sulating body 6. ~`or ~uch ~ design tha u~e of the
full ~moulding castinQ pro. es~ canno~ no~mally bs c~n~i~ered .
It h~ boon ~hown, howev~r, that ~h~ therm~l ln6ul~lti~n
effoct of the high-tempe~ture in~ula~ion 2 ~æ ~u~fioient t~
koep ene~gy 10s9 by the ~to~ low ~nough on th~ ~lde of ~he
oteel ~hlo~t e ~ ~llow the steam to ~o~io~ ~ con~iderab1y
~reater dlstonc~ through the pla~tic gr~nulea b~oro it i~;
used up and un~lo t~ continuo to cau~e compl~t~ ~xpar~ n.
~ecauoo of th~ ~nsul~ting b~dy ~ which gre~tly l~mita he~
flow th~ough the stainl8~s st~ol ~haot 8 it 15 surpr~,31~g to
note th~t it i9 poseibl~ to ~out~ tha ~team to both eides
over the perlphery uf th3 hl~h-templlrature in4ulstlon 2 and
t~ ~llow it to ~xit thro- gh ~ppr~pr~at~ outlot nazzl~s 15
tho ~ide oppoeite th~ ~t~m no~to~ 14. thi~ proce~6 use~ull~
being enhanced in a woy w~ h i9 ~lroa~y known ~n th~ art by
m~an~ of vacuum prea~ur~ at th~ outlet nuz~l~s lS. In th~
13~1b~ Il F'.~-, gE,q Pll~ '3. 11~1. 3~ Y~
8x~mple d~ori~d~ the ~up~rhe~ed stoam i~ ~upplied to the
pla~ti~ ~ranul~s 1~ through the stes~ noz71~o 14 at a
temp~ture ~f 120C, and exlts ~t ~h~ eutlat n~z21es !5 at a
temp~ra~urs of 11~4C ~lch i~ still 5uffici~ntly above th~
expan~i~n ~empesatur~ o~ 105~C cf the plastlc g~anules ~ in
the oxample.
R-adings h~Y~ ~hown th~t the m~tallic ~lls ~ o~ the
s~pan~lon mould 11 aro rcspon~ible fo~ a ma~or p~rt of tho
h~tt less ~y the ste~m. I~ th~ open~g 12 wsre deli~itod ~n
both gid~o ~y ~alls 10 of the ~xpansian mould 11~ whos~
t~mpoIat~re ~lf-evid~ntly mu~t ~lwcys be clea~ly b~low that
of tha ~xp~nsiOn tempe~aturo~ exce~Y~ h~at loas would ~e
unav~id~bls. I~, howe~er, th~ high-temperature i~3~1stion 2
1~ loc~ted ~n the inslde o~ ~he expanBi~n mauld 11 ~nly the
extre~sly 3~all mass of tho thin s~a~nle~-e steel sh~t 8 is
heated up to the temporatu~ of the st~a~ ~h~le the
tempe~ure in the insulating body 6 quickly falls, w1th the
r~sult that only rninirnun~ heat la8s Oe~CtU~6 to the in~lde af
the ex~nsion nlould 11.
I~e~t 103~ a~ tho outelde of ~he opening 12 lrlto the w~lls lC
of the sxp~nston n)ould ll can, how~ve~, be llmit~d by rai81ng
tho tHmpernture of th0 walls 10 auch th9t at, ~o~ exampls,
90~' it i~ æt:ill cl~arly below the expanalon t~mp~rRtur~? of
th~ plastlc g~an~ 13 ~ WhL~h m~ans that promat~l~e ~xpan5ion
~o~ not ~ccu;r durln~ th~ filllnq proce~s. To thi~ end~
el eotricsl he~in9 e~s~ent~ 16 ar~ insert~d in khe walls 1
af the e~pansian mould ll in th~ embodiment sho~n.
After the expsn~ion pr~c~, the expandsd pla~tic ~nod~l wlth
integral hish-temp~ratu~e insulation 2 look~ 80 illustr~t~d
in Fig. 1~ ~lthough in~atead of tha ~le~ve ~ sh~wn thero,
wal~ of ga~ifi~ble plastic m~t~rial sre pro~ont. An
~pprOpr~ate blaek~ng c~n now b~ appli~d to the ~urf~co~ of
Ig~ 16i-6_13'33 k:uhrlPrl.~ Pr 11 Fc~r . 3~ Pll ~ C 88 0~:51
396
-10-
~.
the exp~nd~d pla~t~c ft~teL~i~l, aft0r whlch tha oxpanded
p~a~tie mode~, whioh un~ik~ the ~'inished s~tlcle i8 provld~d
r~lth a g~t~ 6ys~em, la embedded in a ~ id~s~d bed of mould
matrrial ~uch as ca~l~in~ sand and th~la ~ncl~sod in ca~tlr~
~And. If the o~g~ nd i~ ~n~olldat~d by a v~çuunl ~nd/ar
vlbrato~y pro~Ba it olDsaly aur~ound~ ths sur~3ca~ ~ th~
~xpanded ple0~ic ~aat madel ~and th~ free ~ur t o~es D~ the
h~gh-t~mpor6ture insulat1 on 2 . Molt~n metol can than be
poured into the ~asifi~bl~ ~xpanded plast~c via t.h~ ~ate
sy~t~m~ h8raupon the pl~ i3 g~s~flod l~nd repl~ced by the
~nolt~n m~ which ft ll~ ev~ry ~re3 ~p~o betw~9n the heat~
reSi3tont bl~c~<ing of th~ expanded pla~t~ ~edel a~ tl~o
surfac5~ af ~he high-temPe~otura in~ul~tion 2 car~tigU~u~ with
the oxpc~ded plastic mod~l 90 that the de~lred c~ctln~ le
f orm~d .
