Note: Descriptions are shown in the official language in which they were submitted.
2~35~
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Translation:
Title~ PERM~ABLE, POROUS BODY FO~ T~E TREATMENT OF GASES
AND/OR VAPORS AN~/OR LIQUIDS AND METHOD OF
P~O~C~NG IT
5 ~peci ficati,o,n:
The invention rel~tes to a body made o~ a porous
materia~ f~r the ~reatment of gases ana/or v~pors and~or
1 iquids that flow through the body.
In the treatmen~ of gases by the utilization o the
catalytic effect of Cer~ain substa~ces~ porous, cerami~
bodies ~ an appropriate comp~si~ion can also be employe~ in
addit~on to loose bulk material~. Loo~e ~ulk materials a~e
e~ployed prim~r~ly in industry ~OX high vol~me throughpu~s,
while cerami~ bodies can ~e emp~oyed ~or manufacturing
te~hnology rea~ons for smaller volume throughputs~ Since,
depending ~A ~he chemical reac~i~n in a ca~alytic process,
heat is either released or required, bulk materials, and
particularly porous ceramic bodies, exhibit considerable
drawbac~s due ~o ~he poor thermal conduc~ivity of the
20 mat;er~
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PC~ EP90J01118
F~r a ~pecial application, namely the ~reatment of
Diese~ exhau~t gase~, European.Patent ~o. ~,05~,58~ discloses
a soo~ filter ~or ~he trea~ment of ~iesel exhaust gases where
the fil~er i5 composed of a porous, mono~ithic ceramia b~dy.
5 This ceramic body has a plurality o~ mutually parallel thin-
walled channels which are ea~h either closed or open in a
chec~erboard pattern at their end $aaes serving as gas inlets
and gas ou~lets, ~e~pectively. Each channel has one open and
one closed end. When the soot colleoted in such a filter
body bu~n~, it i~ possible, under certain opera~ing con-
ditions, that such high temper~ures develop th~t the melting
temperature of the cerami~ ma~erial is reached or even
exceeded and the cer~mi~ body ~elt~ together, thus ma~ing the
entire ~ilter deviae unusable.
A device ac~ording to European ~aten~ ~o. o,0~6,367
attempts to alle~iate this drawback in that channels of a
larger ¢ross section are disposed in a porous ceramic body,
with molded me~al ~ ments ~oa~ed with catalytically a~tive
mdterials being inserted into t~ese channels. This is
intended to cause the filtered-out soo~ pa~ticles to burn
uni~ormly so that the above~descri~ed excess temperatures are
dvvided..
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PCTJ~P~0~01118
However, in ~o~ cases, porous ceramio ~odies are
required fo~ the p~rely me~hanioal filtering process, ~his
has disadvantages, however, when suc~ filter deviae~ are
ins~alled in motor ~ehicles sin~e it re~uires a considera~le
amount of construction expendi~ures to install the shock
sensitive ceramic filter body in the exhaust cond~it in such
a manner that it will not be damaged or even destroyed by
impaats and shock~ tha~ are unavoidable during operation.
It is now an objec~ of the invention to provide a body
o~ the above-mentioned type with i~proved mechanical and/or
~truct~ral chara~eristics and/or possible appliaations.
This is A~omplished according to the in~ention in that
the pi~rt o~ the body ~hr~ugh which ~low i~ possible i~
composed o~ a permeabl~, porous sintered metal. Such a body,
particularly a ~onolithic body, produaed of a porous ~intered
metal ha6 a mu~h greater mechanical strength than compara~le
ceramic ~odies. Thus, a very much simpler structure xesults
~or ~uch a body Which aan be emplo~ed as a gas filter or a
gas càtalys~, since this body is sel~-supporting i~nd ca~ be
proce~sed like a shaped me~al member, for example fastened by
mei~n~ o~ ~ w~lding pr~cess or welded together of a plu~i~lity
o~ in~ividual bodies to form a larger aomponent. This is of
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PCT/EP90/0111
significance, ~or example, ~or industrial ~pplications.
Another advantage is ~ha~ su~h sintere~ metal ~odles canno~
only be produced in aacurate ~hapes ~ut can also ~e worked on
so th~, due to the minimal diferences in dimenSions,
inst~llation is simplified. Another ope~ational adva~tage of
bodies made of A permea~le, porous sin~ered metal r~sults
~rom the better ~hermal conductivi~y of a metal compaxed to a
bul~ material or a porous c:examic body so ~ha~, for example~
i~ it is employed as a catalyst in catalysis processes, any
heat ~hat is xeleased can be dissipated or heat req~ired for
the pro~e;~; can be introduced . The ~avorable ther~[ al
con~uc:tion charac~eris~ s thtls permit the maintaining o~ a
given te~peratu~e level which, with an appropriate design,
~an be maintained uniformly over the entire ~ody.
According to the invention, ~he porosity of ~he body may
be set to lie between 20 and 80g~, ~hat is within wide limitq.
In this w~y it is posQible to dire~tly influence ~he per-
meability. If used as cat~,ly~;ts, the highes~ possible
porosity will be selected and if used as filters, a lower
20 ~oro~i~y Will be seleated wnich is ~dap~e~ ~o ~he particle
si~e 'Co he ~eparated. A prefe~red porosity lies between 40
and 60%.
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PCT~EPgO/01118
~ his porosity is realized by an appr~priate selaction of
the grain size spectr~ of the metal powder mixture employed
to produ¢e the body. The grain size may lie betwee~ 50 and
500 ~. By employing so~calied sputtery powders, the porosity
in this range can also be in~luenced. In a preferred metal
powder mixture, the grain sizes lie between lOo and 200 ~,
which results in a poxosity of about 50~ or a metal powder
mixture having a gx~in size spec~rum ~etween 200 and 300 ~,
which corresponds to a porosit~ of a~out 60 to 65~. With a
porosity o~ 40 to 50%, ~he required degree of separation for
soot particles i5 S~ maintained in Diesel ~oot filters.
For use as exhaust gas catalyst, the higher porosity is
advisable since then the ~low resistance i5 lower.
Regar~ing the aomposition o~ su~stances, powder ~ixtures
based on chromium, nio~el and iron have ~een ~ound to be
advantageous. For ex~mple, essentially ~he ~ollowing
composltlon:
(a) Cr 15%, Ni 75%, remainder Fe;
(b) ~r 21%, Ni 61%, Mo 9%, remainder Fe;
(c) ~ lG%, Ni 35~, Cu 3%, remainder Fe~
~n ad~ition to ~hese basic s~bstances ~orming the body,
~ich have catalytic characte~istics also for the intended
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purpose with res~e¢~ to thQir chromium and nic~el components,
other ca~al~ti~lly acting ~u~tances, a~ they are known as
ca~aly~ts rOr t~e oxidation of combustible components in the
exhaust gases o~ interna~ com~us~ion en~ines ~n be added to
the powder ~ixtures or additionally applied to the bodies,
for example, by vapor deposition of these substanae~. The
a~ove-stated powder mixtures are preferably employed as
alloyed powders. Thi~ ensures, an the one h~nd, a good
~intering ch~racteristic. On the other hand, it provides
1~ the ca~alytic aharacteristic and the corrosion re~istance
against aggressivç components in ~he exhauSt gasesl In
addition, powdered aomponents of other substanaes, which ha~e
a speaial catalytic effeo~ for the intended purpose, par-
ticularly metal~ and/or metal mixtures, c~n be added to the
alloyed powder. However, these components must a}so be
selected wi~h respeot to their suitability for a sintering
p~oGe~; that is, they mus~ ha~e a melting point in the range
o~ or a~ove the melting point of the basic powder mixture.
Th~ advan~ages o~ s~ch a body become evident also in its
co~bined ~e as catalyst and ~ilter, for example when
employe~ as a Die~el soot ~ilter ~ince here the reduced
$gnition tempera~ure given ~y the cataly~ic components is
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PCT~EP9o/01:118
reached much fas~er so that, even if t;here are only thin
layers of soot, ~he ~iltered ou~ ~oot components will burn
o~. Moreover, this brings abou~ the direct ~onsequence that
the den~ity o~ the depo~it i5 less an~ ~hus there exists a
high gas permeability ~nd correspondin~l~ a reduced flow
resi~tance. A~ the same time, the ~flow ch~nnels" in the
8~ ntered metal extend over a relati~ely long leng~h, ensurin~
relia~le separation of even the ~mallest par~icles when used
as a Die~el soot ~ilter, and a large contact area ~or the
exhaust ga~ to ~e treated when used as a catalyst. Another
advantage o the body made of porous sintered metal is that,
with the appropria~e gr~in ~ize spectrum of ~he sta~ting
powder, the outer Pa¢es o~ the body are rough so that better
~hermal ~onduc~ion pr~pertie~ and thu~ improved opera~ion
re~ult.
Another advan~age is that the aacumu~ation of heat,
dr~aaed in oonnection wi~h the ceramic bodies when employed
4~al~tically or as ~ filter, for examplè upon burning o~ the
~oot layex, is avoided due to the bette~ ~hermal conduction
o~ a ~etal ~ilter body. Because of the good ~ermal conduc-
t~ity of ~he ~intered metal bodies, the he~ rele~sed
generally over a limi~ed area due to the combustion of the
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Diesel 500t deposits is released fas~er to ~he exhau~t gas
stre~m and primarily to the adjacent re~ions of the body so
~hat the combustion pro¢es~ expands more rapidly o~er the
surface and thus is made more uni~orm as a ~hole. Another
advan~age is that the metal powder mixt~re ~or the produotiQn
of such ~ sintered metal body ~an alread~ be given such ~
composition that the metal powder mixture alr~ady ~ontains
~uch metals and metal oxides ~hich, as catalySts, enhance the
reduction of the ignition ~empera~ure of the ~iltered-out
Diesel soot par~icles and/or ~he comhustion o~ gaseous
conl;aminants .
An advanta~eous ~eature of the i~vention provides that
the porosi~y, with referen~e to the directi~n o~ flow o~ the
ga~ to ~e ~x~ted, is dif~erent at the inlet end than ~t the
15 outlet en~. In thi~ way, i~ is possible ~o in~luence the
~low ~urv~, particularly for ~ataly~ic pro~esses. If there
i~ an increase in volume, the g~eater porosi~y ~u~t exist at
~ ~he outlet end. I~ there ~s a reduction in volume, the
arrangemen~ mus~ be reversed. I~ employed as a ~ie~el soot
~ilter, the greater poro~ity must be present at the inlet end
~ n ord er t~ permit the particles to pene~ate as deeply as
po~sible, thus ~aking combustion more uniform.
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To si~plify the manufaature of ~his permeab}e, porous
sintered metal body, i~ i~ advisable for the bod~ to be
~omposed of ~ ast two firmly sin~ered together lay~rs of
different porosity so that the porosity changes in stages~
In a &uitable embodiment o~ the inven~ion for use as a
catalyst~ the sin~ered metal is ~ompo~ed at least in part o~
a catalytically acting material. However, i~ is o f par-
t~cular advan~age i~ the catalytically acting material is
applled as a layer onto the basic ma~e~ial defininy the pore
10 ¢hannel~, at least in the suxface region of the porous body.
This can be e~fe~ed by vapor-deposition or by sin~ering i~
on. I~ ~intering is employed, the pore channels of the
porou~ body a5 a whole or b~ l~yers may be provided with a~
appro~riate coating so ~hat the per~orma~ce of the catalytic
treatment o~ gases and/or vapors that are ~ree o~ solids can
be improved.
In another embodiment of the invention it is provided
that in th~ part o~ the body composed o~ permeable, porous
~intered metal, there is disposed at least one channel
having an impe~mea~le wall. In this way, lt becomes pos-
sible, by the direc~ additio~ or removal of heat, ~o in-
~luence the ca~alytic process within the sintered body even
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pcr/~p~O/01118
if the bodies are lar~e. The ~h~nnel may be shaped ~s a tube
in the molded metal powder blank so that ~he bo~y is
"shrunken~ onto the tube during the sintering process and a
good thermally conducti~e aonne~ion exists.
S As a ~urther ~eature of the inven~ion, it i5 provided
that the body is configured as a monolithic ~ody and is
provided with a plurali~y of channels whi~h pre~erably pass
through the body parallel to one another~ It i~ particularly
advisable for ~he width of the channels, which preferably
have a sg~are cross ~ection, to be app~oximately equal to the
wall thickness o~ the partitions ~eparating two ~djacent
channels. ln this way, there results, on the one hand, a
~avorable i~luence on the exhaust gases, particularl~ in
ca~e~ in which the exhaust g~se~ to be treated must either be
iltered or in which the exhaus~ gas flows through the
partition~ in order to increase the period o~ d~ell on the
catalytically a~tive surface and, on the other hand, a high
strerlgth ~nolithic body.
Since the body m~de o~ porous sintered metal h~s a high
mechanical strength, it is pos~i~le to install it in a
hou~ing in a sel~-~upporting ~ann~r, or exar,lple so ~hat one
end o~ the body is rigidly seated in a housing wall and the
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pcrJEp~o/olll8
o~her end is displa~eably held in the other housing wall.
Thus the body is able to freely expand in leng~h under
ch~nging temperature influences so that no thermal stresses
can deve-op~
In a suitable emhodiment invalving a monolithio ~ody in
which the chann~ls are each al~ernatingly open at one chann~l
end and closed at the other ~hannel end, the inven~ion
provides that ~he ~lo~ure o~ the one p~rt of the channels is
e~ected by a shap~d-on end ~ace forming the ohannel ends and
a~ ~he other end by a perf~ra~ed plate whiah is set in froht
o~ the channels. Thi~ has the advan~age ~hat the closing of
the channel ends at one side can ~lready be e~ected ~uring
manu~aature, that is, in one process phase, while the closing
o~ the other e~d is ef~ected by an additional comp~nent which
adYisably may simultaneously also be used to fix the body in
the housing.
~ feature of the inven~ion there~ore provides that the
perforated plate is composed of a punahed sheet ~etal plate
~n which the regions ~onning the alosure are e~ah ~ormed by
an embosæment engaging into ~he associated channel openings.
While it i~ pos~ible in principle, to ~ix the body at
one end ~o a housing wall by means of a welding process, a
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P~T/EP90~01118
particularly advantageous ~eature o~ the inven~ion which is
~avorable ~rom a manufacturing technology poin~ o~ view
provides th~t the end of t~e body to be ~ixed to the housing
includes a shaped-on, continuous holdin~ collar. Such a
holding collar no~ ~nly simpli~ies installa~ion, sinoe the
body is initiall~ ~eld in a form-locking and centered manner
already when it is inserted into ~he housing, welding is also
easier i~ ~he conn~ction is made by welding. ~he arrangement
of a holding collar also makes i~ possible to create, instead
o~ an expe~sive wel~ed connection, a simple form-lo~king
~onn~ction~ since the body can be clamped i~ by way of the
holding collar. As a ~itable reature it i5 her~ provided
tha~ a~ leas~ one end face of the holding oollar is given a
conically tapered shape. ~hi~ si~plifies ins~allation sin~e
with a correspondingly conically shaped con~act sur~ace at
the housing, the inser~ed body is able to center itself and
arrange itsel~ parallel to the housing axis.
A ~xm-lcc~ing connection according tO the invention can
be realized in that the body is placed against the as-
~ociated housing wall by way o~ its holding collar and ac~rrs~ponding press-on ring~
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PCT/EP90/01118
In another ~mbodimen~ it i~ provid~d a~aording to the
invention that the po~ous body in~ludes at least one tu~ular
bod~ which i~ closed at one end and i~ oriented in the flow
direction in a flow guid~nce housing. Such candle-shaped
tubular bodies made of s~ntered metal haVe a much higher
mechanical strength than ~eramic elements and therefore are
better suited, ~or example, ~or use in ~iesel engines,
particularly mo~or vehicle Diesel engine~. They may be
arranged in the ~low housing in multiple number~ parallel to
one another so that the porous sintered body permits the
reali~ation o~ a large flow cros~ ~ection even in a small
space. This resul~s ln a very much simpler structure for
~uch an ~X~aust ga~ filter since the ~ubular bodies are self-
~upporting and can be pro~essed in the manner of a metal
1~ ~olded aomponen~, for example, can be fas~ened by welding~
Another adva~t~ge is that such sintered metal ~odies canno~
only be produced in accurate shapes ~u~ can also be wor~ed so
that, due to the small differences in dimensions, ins~alla-
tion i5 simplified. Another o~erational advantage of ~ilter
boAie~ made o~ a porous sintered metal results fro~ the
better thermal con~U~iVity of a metal compared to ~ ceramic
mat~rial so that here the reduced ignition te~per~t,ure
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P~ 3P90/01118
prede~ermined by the ca~alytic componen~s is reached ~uch
faster and the fil~ered out soot particles hurn of~ already
when thexe a~e only thin layers of soot. ~oreover, this
leads to the direct aonsequence that the densi~y of the
deposit is less and thus high ~as permeability ~nd a co~-
respondingly lower ~low re~istance exists. ~he parti¢ular
~dvantage o~ a sintered metal body is that in its case a high
por~ity o~ almost 50~ is realized together with a fa~orable
~low re~i~tance. At the same time, the ~flow channels" in
1~ the sintered metal have a relatively long length so that
reliable separa~ion o~ even the smallest particles is
ensured. Another advantage of the tubular bodies ~ade o~ a
porous ~intered metal i8 that, with an appropriate manu~ac-
turing process, na~ely pressing the powder mixture around a
steel core with ~he aid o~ an elastic cu~, the ex~erior
~ac~s o~ th~ tubul~r bodies are rough, resulting in better
thermal oonductivity properties and thus improved operation.
Since the i~dividual tubular bodies made of porous
~i~terQd ~tal. have a high mechanical strength, it i5
possi~le to inst~ll the tubular bodies in the housing in a
self-supporting manner. As one feature of the invention it
is there~ore provided that the tubular bodies are fastened to
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PC$JEPgO~Oll~
'che housirlg walls at at ~east one end, preferably at bo~h
ends. In this connec:tion, it is par~icularly advisable ~or
the ~ubular bodies ~o be fixed rigidly to the one hou~ing
wall at their one end and tc) be displac~eably held in the
other housing wall at their other end. ~hus, eaçh tubular
body i~ able to freely expand in length under chan~in~
temperature influences æo that no therm~l s~e~es can
d~velop. ~he rigid fixing prefera~ly ~akes plaae at the open
end of the tubular body.
Aacording to the invention, the open ends o~ the tubular
boaies are held in a housin~ partitio~ in whi~h only the
~ube openings form passages for the exhaust ~as. I~ at lqast
two housing walls are utilized to ~asten the tubular ~odies,
then a rurther ~eature o~ the invention provides that the
tubular bodies are held in the region of their closed ends in
at least one ~urther partition which is provided with push-
through openings ~or ~he tubular bodies and additionally with
exhau~t ~ pa~age ~penings~
While it i~ po~ le in principle to fix one end of the
~0 tubular bod~ 85 to the respective housing partition by means
o~ a ~elding process, ~ parti~ularl~ advantageous feature of
the invention which is favorable ~rom a manu~ac~uring
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Pc~/Ep9o~ollls
~echnology aspe~t provides that the end of the ~uhular body
~o be fi~ed to ~he housing is provided with a ~haped-on
con~inuous hol~ing collar. Such a holding ~ollar not only
simp~ifies ins~allation, sinae the tubular bodies are
initially held in a form-locking mannex as soon as they are
inserted into corresponding ~ores in the respective housing
wall. The ~nnection by means of a welding process simpli-
fies the welding so ~ha~, for example, meahani~ed welding
proce~es o~ the type of a burn-off butt-welding proaess or
the like can be e~ployed. However, the arrangement of a
holding colla~ also makes i~ po~sible to create a ~imple
2~rm-loaking con~catio~ instead of the expensive welded
¢onnection, since the tubular bodies aan be cla~ped in by way
of the holding collar. A suitable ~eature here provides that
~5 at lea~t one end face of the holding collar is given a
coniaally tapered ~h~pe. This simpli~ies ins~all~tion
since, with corre~pondingly conically shaped passage bores,
the ins0r~ed tubular boaies center themselves and arrange
th~ lves parallel ~o one another.
24 A ~or~-loak~ng aonnection can be made according to the
invention in that the tubular ~odies are ~ixed by way of
their holding collar in the associated housing partition by
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PcT~P~0~01118
means of a press-on p~ate pro~i~ed with ~orrespo~ding
openings.
As a further advanta~eous feature of the invention, it
is pro~ided that the respective exterior ~ace of the tubular
bodies is smoo~hed at least a~ one end by a prefera~ly
mechanical proces~. Pre~erably, that end o~ the tubular ~ody
is smoothed which is displaceably he~d in a housing partition
so that here it is possible for the ~u~ular body to properly
expand undex the in~luence o~ temperature.
As a further feature o~ the inven~ion it is provided
that at least ~he end o~ the tubular bo~y provided with a
holding collar has a dif~eren~ ¢ompo~ition o~ ma~erials which
is directed toward increased strength. In this eature as
well, the advan~age o~ using a metal ~lntered ma~exial for
such porous bo~ies is evident. The possibilities of the
manu~acturing proaess permit the use of, ~or example for the
~tening end o~ the tu~ular body~ a tigh~ly sintering and
thus mechanically highly s~ressable powder mi~ture which is
~hen ~ollowed by a powder m~xture that meets the de~ired
zo poro~ity reguirements~
As a method ~or producing porous bodies from sintered
metal, par~iau~arly monolithiq bo~ies having a plurality of
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PCT/~P~0/01118
preferably para~lel extending channels/ the invention
provides th~t a flowable metal pow.der mixture havin~ a grain
size spectrum between 50 and ~0 ~, mixed with a maximum o~
~% (by weigh~) phenol containing liquid ~ynthetic resin i5
blown by means of compressed air, pre~erably injected,
through an opening into a mold which corresponds to the
outer contour o~ the body and whose inner wall is provided
with ~olding elements corresponding to the channels to be
fo~med. ~hen the filled mold is supp~ied wi~h a catalyti~al-
ly acting medium ~or hardenin~ the synthetic resin andtherea~ter the molded blank is remo~ed ~rom the mold and
slntered. With su~h a process it is possible to produce a
porous blanX having a complicated ex~erior ~ontour and/or
relatively thin walls, wi~h suah blank, after unmo~ding,
being manageable wi~hout di:e~iculty and sinterable. Xf the
mold is appropriatel~ longitudinally separable, the process
AlSO permits the ~haping o~ a continuous holding oollar to
~he ou~er circum~erence. The ~ompact~on of the metal powder
e~eoted durlng the blowing-in proc~, particularly during
the inje~tion o~ the metal powder into the mold with simul
taneous removal o~ the air contained in the mold ahamber,
ensures a uni~orm grain distri~ution so that an essentially
PCT/EPgO/01118
uniform porosity is realized over the length as well a~ the
aross se~tion~ Surprisingly, it h~s been ~ound that the
thus produced ~ank can be s~jecte~ to ~he sintering proces~
without auxiliary or supporting mol~ he molding process
5 ~urther permits the provision of any desired a~oss-~ea~ional
configuration fo~ the ahanne~s as well as for the outer
contour o such a monolithic body. Thus, in addition to
circular cross seoti~ns, oval or elliptiaal or al~o poly~on-
al, ~or example rectangular, cross sections can also be
pr~du~ed. By blowing in charges of metal powder~ having
di~erent grain size ~pectra, it i~ possible to produce a
layered ~tru¢~u~e in the blan~ with di~ferenceS in porosity.
I~ the sintered metal ~ody is to include channels
having i~p~rmeable wal~s, the molding elements are ap-
lS ~ropriately &haped tu~es which are releasably connected withthe mold, are remo~ed togethe~ with the b~ank, and take part
in the slntering proces~ so that they are ~irmly bonded into
the porou~ ~intered metal body~ The blowing or injeation
proces~ ~or the introdu~t~on of the metal powder ~i~ed w~th
~0 the ~ynthetic resin liguid here makes it pos~ible to also
produce compliaa~ed tubular ~hapes, ~or example a tube coil.
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~CT~EP9OJo~
The metal powder mixture, for whose composition examples
were ~iven abo~e, is now introduced under pressure in~o a
pot~ e mold. The introduction may ~e e~ected, for
example, in tha~ the metal powder ~ixture is fluidized in a
reservoir container and is then ~lown into the mold with ~e
aid of a compressed air jet. Sinae, however, the danger o~
demixing exists du~ing the ~luidizing process, it is ad-
vi~able ~o~ the metal powder mixture to be in~ected into the
pot-~ike mold. ~his is done in th~t the me~al powder
quantity to be molded i~ introduced into a preliminary ~essel
that i~ aonnected with the mold to ~e filled and i~ then
charge~ with compre~sed air so that, due to the sudden
expan~ion, the guan~ of metal powder ~ontained in the
~reliminary container i~ injected into the mold at high
~peed~ ~he mold itsel~ is here not charged by the compressed
~ir pres~ure. The atmospheric air aontained in the mold is
removed through a~ropriate ventilation opening~ or ventila-
tion channels.
81n¢e a maximum ~ 2% ~by we1ght) phenol containlng
syn~hetiç resin in l~uid ~orm is incorporated in the metal
powder mixture, the ~illed mold is ~apor-treated with a
catalytically acting medium, ~or example tertia~y amine, so
- 20 -
l~CT/EP90/01118
that the ~yntheti~ resin hardens. The hardened synthetic
resin now holds the individual metal par~iales firml~
together so that the mold can be opened and the ~lank
removed. The strength is here so high that the blanX aah be
worked without difficulty in the subse~uent processing
phases. I~ so-called ~puttery powders are employed/ the
individual metal pOwaer particles are not only held together
by the hardened synthetic resin par~ia~es, the~ ~re also
mechan~cally ~Iclamped t~getherll in the ~bove-described
injection process. ~he result o~ this is that the molded
bO~ can ~e sln~ere~ ln ~he convention~l m~ er~ f~r example,
in an em~edment, prefer~bly under a va~uum. I~ is p~ssible
to produce such molded bodies very true t~ di~ensions.
As a further feature, the method acaording to the
invention permits the particularly advantageous introduction
o~ ~he ca~alytically active components. In thi~ case, the
component~ are mixed With the liquid synthetiC resin so that
the ~etal powder mixture itself doe~ not contai~ these
com~onents. ~rter the molding process, the ~ata~y~ically
~ctive components are thus disposed wi~hin the synthetic
r~sin layer, in each case on the surfa~e o~ ~he metal
p~rticles. ~ring sintering, the synthetic resin i~ driven
_ z~, _
3 3 ~3
PC~/EP90/01}18
out while the catalytically active componen~s are sintered
onto the ~ac~s de~ining the p~re channel~.
~ he term ga~ in the ~ense o~ ~he present invention is
understood to mean gases ~nd gas mixtures in the a~tual sense
as well as vapors and ~as~s çharged with ~olids. ~n conneo~
tion with liquidg, it may ~e important to evaporate them in
or by way ~f such a porous body so that there is no cataly~ic
e~fe~t, but addi~ional heat i~ supplied throug~ shaped-in
channel~ having impermeable wall~.
The inVention will now ~e described in greater detail
with re~erence to e~odiments thereo~ ~hat are illustrated in
~hematic drawing igures. I~ i~ shown in~
Fig. 1, a longitudinal sectional ~iew thro~gh a gas
channel with inserted monolithic body;
Fig. 2, a partia~ top view, to a larger ~cale, of the
~rQ~ end o~ the ~o~olithic body in which all
channel~ extend ln the longitudinal direct~on;
Fig. 3, a longitudinal ~ectional view of a monolithic
body ha~ing channels that are closed at
alternating end~;
Fig. 4, a ~op ~iew, to the same scale, of the ~ront
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~ " ~,7 ~ 2'~
PCT/~:PgO/01118
end of a monolithic ~ody havin~ ~hannels that
are closed at al~ernating ends;
Fiq. 5, a lon~itudinal se~tional view of an em~odiment
in ~he form of an assembled filtex cartridge
for a Diesel soot fil~er including perme~ble,
porous bodies confi~ured as ~ubular bodies;
Fig. 6, a front view seen in the direc~ion of arrow A
of ~i~ure 5;
Fig. 7, a fron~ ~iew seen in the direc~ion o~ arrow B
o~ Figure 5:
~ig. 8, a detail X of Figur~ 5 to an enlar~ed scale;
Fig. 9, a sectional ~iew o~ an embodiment ha~ing
ayers o~ di~erent poro~ity;
~ig. 10, an e~bodiment including shaped-in channels
h~ving impermeable w~116.
Figure l show~ an embodim~nt as i~ aan be emplo~ed as a
catal~t ~or the treatment o~ ga~es, ~or exa~ple for the
exh~u~t ga~es o~ inte~nal combu~ti~n engines. Here, a
monolithic, porous ~intered mstal body 2 equipped with a
plu~ality o~ parallel extending continuous channels 3 is
disposed in an exhaust gas conduit 1. At its one end, the
-- 23 --
'~3~3~
PC:'r/EP~ Ot 01118
body 2 has a continuous, external hulding collar 4 ~y mean$
o~ which it is form-lockingly ~astened to a holding ~ube 5.
The holding tube 5 is provided with a cor~espondin~ conical
receptacle 6 in which ~he holding collar 4 is fastened by way
of a corre~ponding, oppositely conioal holding ring 7.
Holding tube 5 i5 ~ixed to exhaus~ gas pipe ~, for example
by welding, The conneetion between hol~ing ring 7 and
holding tu~e 5 may here also be made by welding, ~or example
by dot welding. This purely ~orm-locking a~tachment has the
advantage that thermal stre~es due to ~ea~ly f}uctuating
temperature di~srences in the ~a tening region are avoided.
~ owever, the ~ody may also be welded directly ~o holding
tu~e g in the region o~ its holdin~ collar.
~he othe~ end 8 of holding tube 5 is supported 1009ely
in exhaust gas pipe 1. Body 2, in ~urn, is s~ported in ~he
holdi~g tube, ~or example by way of punched-ou~ t~b~ 9, so
th~t holding tube 5 as well as ~ody 2 are able to ~reely
expand in length.
The exhaus~ gase~ to be treated flo~ through ~ody 2, for
exa~ple in the direa~ion o~ arrow 10, undergoing the desired
xeactlon proae~es initiated by the a~lytic components o~
She ~int~red metal and possibly b~ ~n additionally applied
- 24 ~
~3~
PCT~EP90/01118
aoating o~ ~a~alytically aative materials whiah are not
contained in the s~arting powder mixture. ~he coating is
here applied i~ such a manner that the pe~meable pores are
not clogged.
Figure 2 shows i~ a frontal ~iew seen in ~irec~ion of
arrow A the ~rrangement of ahannels 3 in body 2 in a sche-
matic illustration.
Pigure 3 snow~ a somewhat modified embodiment of body ~
a~ it is employed, for example, for ~iesel soo~ filters. In
thi~ embodiment, ~h~ channels in body 2 are not arranged to
be continuous ~ut are clo~ed alternatingly at one end and the
othex Bnd o~ the body so that channel ~a is open only towa~d
one end and the adjacent channel 3b is open toward khe other
end.
Figure 4 is an enlarged and again s~hema~ic ~ront view
which indiaates that channels 3a and 3~ are alternatinqly
~losed and open in a mutually offset chec~erboard arxange-
ment. In ~he illustr~ed e~bodiment, ~he closure o~ the
channel~ at the end indicated by arrow 11 is produced already
29 during manufacture o~ body Z, namely in such a manner that
the m~lding n~e~les employed in ~he produ~tion mold to form
the channel~ 3b are shorter than the moldin~ needles employed
- ~5 -
.
.
6~
PCT~EPgO/01118
for the produc~ion of channels 3a so that ~he free ends of
the molding needles are covered by sintering material~
However, it is ~lso possible, s~rting wit~ a body as shown
in Figure ~, to p~od~ce the re~ ed closure by th~ insertion
5 of plug~; in a further proc:ess step.
~ orresponding1y, at the end of body ~ identified by
arrow 12, channels 3a are closed and ~hannels 3b are open.
In ~he illuatrated embodimen~, the ~losure is here ef~e~ted
~y a per~orated plate 13 into which the aorresponding passage
10 openings 14 have been punched so ~ha~, when see~ ~rom the
~ron~, the same con~iguration re~ults as in the fron~ ~iew
along arrow 11, ~3xcept that: the openings are c:orrespondingly
exchanged here. Per~orated plate 13 may ~e provided with
embossments lS in ~he re~ion of the ~hannels ~a to be closed,
so that here the form lock be~ween body 2 and perforated
plate 13 which simultaneousl~ serves as fas~ening means is
improved.
The exh~ust gas ~lowing in exhaust gas conduit 1, for
exam~le, in the direction o~ arr~w 10 now en~ers channels 3b
a~ ~he end ~a~e, flows through the partitions between the
in~i~idual adj aaent channels and le~ves the bod~ through the
opsn rs~r enAs of channels 3a ~s indicated by the curved
-- 2~ --
'3~
~CT/EP~0/01118
arrows. In use as a Diesel soot ~ilter, ~he soot par~icles
oontained in the ~xhaust ga~es are re~ained on the interior
wa~ls of channels 3b. Since the ho~ exhaust gases heat
sintered metal body 2 which contains ~a~aly~icallY a~tive
material to a tempera~ure which lies in ~he range o~ the
ignition temper~tU~e, reduced ~y ~he catalys~s~ for Diesel
soot, the soo~ Will burn of~ even if the ~oot layexs are
relatively ~hln~ with the te~perature incr~aae as a result of
the burning continuing the ~urning of ~he soot deposits over
the entire channel surface wi~hin the shortest possible time.
Due to the high porosity of such a porous sintered metal
body~ the embodimen~ ~hown in Figure 3 C~n a~so be ~sed as
an exh~u~t gas catalyst ~or the treatment of the exhaust
g~ses o~ Otto engines~ Due to the fact that the exhaus~
gases, in contra~ to in the embodiment of Figure ~, do not
flow only along the channel ~urface bu~, due to the alternat-
ing closure o~ the individual channels, must also flow
th~ough the par~ition~, the time period during which ~he
exhaust gases come in contact with the ca~lyticallY ac~i~e
sur~a~Q5 is extended, thus ~ur~her improving the ~nversion
o~ harmful su~stances.
- 27 -
,
2 ~ Q3
PC~P90/01118
~ i~ure S ~hows in a lo~gitudinal seotional view an
embodimen~ for use as a filter ~artridg~ for~a Diesel soot
fi~ter which is in~erted into a eorrespondin~ly widened
por~ion of the exhaust gas conduit o~ a Viesel engine. The
filte~ cartridge is essen~ially composed of a ~low ~uidance
housing 16 which has a cylindri~al cross section - a shown
hexe - or al50 so~e other cross~sectional configuration, for
example, oval. The one end face is terminated by a housing
p~rti~ion 17 a~d the other end face by a housing pa~tition
18, which aarry in aorresponding openings a plurality o~
parallel extending tubular bodies 19 made of a porous
sintered me~al. The ~ubular bodies 1~ are open at one end ~0
and closed at the other end 21. Partition 17 is here
prov~ded with ~as pas~age openings 22 which are identical to
the opening~ in tubular bodies 1~, as evident in t~e front
Yiew~ o~ ~igures ~ and 7. Housing partition 18 is provided
With pas~a~e openings 23 through which the end 21 o~ tu~ular
bo~s 19 is pushed and the remaining spaces axe provided
with ga~ passage openings 2~.
ThB ~hau~t ga~es are now able to ~low ~hrough ~he
~ er cartridge ~hown in Figure ~ from ~he directioll of
arrow A as well as ~rom the direction of arrow B~ If they
- 28 -
.
t~@3~3~
PCT~EP~o/01118
~low in the direction of arrow A, the exhaus~ ~ses enter the
interior o~ tubulax body 1~ and ~low, as indicated by arrows
25, through t~e porous walls of the ~u~ular bodies and en~er
through ~aa passage openings 24 into ~he connected exhaus~
gas conduit which is not shown in detail. Howe~er~ the gas
may also flow ~hro~gh the filter body from the other side so
that ~he ~low would then ~e correspondingly reversed.
Tubular bodies 1~ aXe now fixed in the parti~ions in
such a ma~ner that one tube end is fixedly connected wi~h a
~ousing partition and the other tube end i~ held in a
corresponding opening so as to b~ freel~ displaceable. I'he
~as~ening may o~cur, for example, by welding the respective
tube end. In the il~ustrated embodiment, howe~er, a par-
~icularly advantageous ~orm-locking connection has been
sele~ted. As ~hown in Figu~e ~, a continuous holding ~ollar
26 is shaped to eac~ tubular body 1~ in the region o~ its
open end, wi~h the two end faces 27, 28 of the holding
colldr having a conica~ly tapered shape. The housing
partition 17 is here ~ade of two parts. ~ach wall portion is
produced, ~or example, by a punching process in whi¢h the
hol~ an~ their conical contact faces for the end faces 27,
~8 o~ holding collar 2~ and a connecting flange 29 are
- 29 -
,.f~ fz ~
PCT/EP90~01118
produced in one process step. Both wall portions ar~
identical 50 that initially wall portion 17a can ~e conne~ted
with hous~ng 16, for example ~y welding, ~nd then housing
partition 18 i~ also connected wi~ the housi~ Therea~ter,
tubular ~odie~ 19 are inserted in the direction o~ arrow A,
w~ll portion 17b i~ put on ~hus aentering ~he conical end
face ~7 and then the bodies are we~ded to housing l~.
In ord~ to increase the resistance o~ the arrangement
again~t damage and ~hocks, an additional p~rtition, not shown
in detail here, can be pro~ided as a supplemental measure in
the ~orm o~ a housing partition 18 whi~h is disposed in ~he
hou~ing between parti~ions 17 and 1~.
Since the ~ur~ace of tu~ular body l~ is relatively
rough, roughness peaXs projeat through the developing ~oot
15 layer so that, in spite o~ the heat insul~ing e~fect of the
500t layer, heat from the exhaust gas s~xeam is introduced
into the tubular ~ody and thus the ignition tempe~ture is
realized e~rly. Burning ~hus occurs already if there is only
~ thin deposit and thus ~ore frequently and as a whole more
uniformly.
The sahem~tic illus~r~tion in Figure 9 ~hows a permeable
porou~ monolithic sintered metal body 30 disposed in a flow
- 30 -
~J~3 ~
PCT/El?gO/ 01118
channel 31. In ~he i~lustrated embodiment, body 30 has such
~ compo~ition ~ha~ it aontains components which have a
catalytic effect with respect to the gas ~o ~e treated and
are in~erted into the bOdy in a manufacturing mannex des-
cribed in gre~ter de~ail abo~e. The geometric shape of thesintered me~al body 30 depends on the process technology
condi~ions which need not be considered here in detail. ~n
the illustrated embodiment, the body is composed o~ three
layers, with ~he ~irst layer 30a, wi~h respec~ ~o ~he
lo dire~tion o~ flow (arrow 32), having a high porosity, the
s4cond layer 3Ob a ~omparatively lower porosity and a third
layer 30a having a further reduae~ porosity. Since these
three layers are ~uc~essively brought ~ogether in the above-
de~cribed in~ection process with appropriately matched metal
~owder ~ixturés a~d the thus resulting three-layer blank is
then sub~ected to the sin~ering process, it is ensured that
~he three layers ~in~er firmly together and thus a solid
~orloli~hic body is available which has a correspondingly
~raduated pore structure. Such a layer stru~ure may al~o be
employed, ~or example, ~or bodies as shown in, and described
in connectton with, Fi~ures 1 and 5.
- 31 -
P~/EPgo/o~
The schematic illustration o~ the embodiment o~ Figure
10 shows a permea~le, porous ~ntered me~al block 33 in
which channels 34 are ~ormed which ha~e imperme~ble walls.
If, for example, a bloak of such con~iguration i~ again
inserted into a flow ch~nnel 31, i~ is possible here to
condu~t a ~owable thermal conductor through the channels ~4
having the impe~meable walls so a~ to supply neat to or
remove heat ~rom the channels dependinq on the prooess ~o be
per~ormed, By utilizing the good thermal ~on~uc~i~ity of a
sintered metal body wi~h the appropria~e distribution o~ Su~n
ahannels, a uniform ~emperature distribution c~n be realiæed
over ~he en~ire cross-sectional area. With respect to the
treatment process ~o be performed, channel 3~ may ~e mold~d
direa~ly into those regions o~ sintered me~al body 33 which
~5 require a positive supply or ~emoval of hea~.
In the manu~acturing proce~s descri~ed in detail above,
in whiah a metal powder mixture mixed wi~h a synthetic resin
liyuid ~s a bindex i~ injected into a mold, one is not forced
to provide linear and/or s~ooth-sur~aced channels 34.
~a~her, the procefi~ also permits the use of other ~pes of
channel ~hape~, ~or example in the ~orm o~ tube coils or the
li~e, ribbed tubes or the li~e~ The shaping ~nd positioning
- 32 -
j éP
PCr/EP90/0111~
within the ma~ufaaturing mold m~st mere~y be effec~ed so that
it is ensured that ~he man~facturing ~old is ~illed uniformly
dur~ng ~he injection process. Metal tub~ are e~ployed with
preference, wi~h me~als ha~ing ~o be u~ed hsre which are able
to with~tan~ ~he ~in~ering ~e~perature. Instead of tubes,
other bodies can also ba shaped in ~hi~ way into the porous
~intexed body. For example, rod-shape~ eleatrical heat
conductors or also only pin-~haped fastening mean~ whi~h
~roject beyond the ex~erior face o~ the ~intered body.
- 33 -
