CA2060430A1 - Bag filter with thermoplastic tape-sealed sewn seam - Google Patents

Abstract

ABSTRACT
A Bag filter comprising at least one sheet of a filter medium, preferably n polypropylene high dirt capacity filter medium, formed into a bag configuration with an opening, an inside surface, an outside surface, and at least one seam formed at adjoining filter medium portions which been sown together, wherein said seams are sealed with thermoplastic tape that has been heat-sealed to the adjoining filter medium portions. A method of preparing such a bag filter is also provided herewith.

Description

J~N 31 '92 15:01 202 LEYDIG VOIT M P.~
-- 206~3~

BAG FI~ER WI~X ~ERMOP~A8TIC ~APE-SEA~ED BEW~ 8EA~

Thl~ lm~nt~on rc~ls~ to ~ b~g ~llt~r com~ ng at l.e~t one ohe~t o~ a fil~er ~edlum 5 ~o~e~ into a bag con:eigu~tlor~ w1th ~BWl~ ~e~m~, wh~rein ~ th~rmo3~1a~ic ~ h~ b~sn heat-~loal~ t~
the ~d~olrlln~ p~rtione o~ ~h~l ~iltor m~âlu~ at ~h~
a~am3~ ~ha pr~ent lr~ven~lon aloo aor,cern~ a ~ethcd o~ pr~ar~ng ~uah a ~ag ~iltf~r.
~0 ~W:~
~ ag ~ilterw Ar~ typ~call~ ~orm~ ro~ oh~ot~ o~
~loxibl~ mat~rial whic:h sr~ ~oln~d togeth~r, u~ually by ~ewln~ ~uch ~h~t~ togeth~r. For ~x~ , b~y ~iltar~ p~p~r~d ~rom high dirt capacit~
15 poly~;ropylone ~ilter m~ad~ ohe~to whlah h~ Q~n ~0wn ~o~stho2~ ~rs ~olnmercially ~ R f~o~ Pall Corpora~on ~Glen Cov~ w York) tlnd~
tr~a~Rrk Prorile~.
t9hl~o in most Uil;lQI~ th/~ ~wn ~m~ o~ ~uch bag fll'c~r~ ~o not ~ ct ~h~ lntQgr~ty o~ tho b~ -~lt~ , th~rh arQ ~ome ~n~'ca~c~ ~n w~l~ch th~ ~wn ~am~ o~ ~on~nt~onal l~ag fil~er~ can bsc:~m~ 1~ Xa~
p~thway~ depunding u~?on th~ na~ura o~ ths ~lul~n b~in~ ~llto~d and th~ ~re~ure ~t whiah ~ltr~t~on 1~ being ~ra~t~ h~u~h ~wn ~qarn~ ~y ~om~ti~ om~ le~ag~ pathways, ~h~ all~wing uJ~llt~d ~lul~ to l~ypA~ th~ ~ltær medid, th~
pr~va~ling c:onvGntlon~ll p~aatlc~ o~ ~r~p~r~n~ bag ~ilt~r~ c~ntlnu~ to i~olv~ a~n l~e~All!C~. ~I!h~s prs~ss~n~ tlhQ re~ul~ o~ the n~d ~or th~
ox1~t~ncQ ~ a atron~ ~e~hania~l ~on~ b~t~earl th~

.
, JRN ~1 '92 15:02 202 LEYDIû UOIT 11 P.05 20~0430 ~ilt~r ~edium portion~ ~oinod. ~og~th~ to ~orm b~g ~ilt~r oo a~ to ~n~bl~ ~uch ~g rilt~r~ 'co be usod ~Ln rugg~d enviror~ment~J. 8uoh ~ ~tron~
m~shan~a~l bond ~nnot g~ner411y b~ pro~ o~ by 5 gluing or heat-~ealing t~ ~ilt~r m~dlu~ ehe~t~
ln~tea~ o~ ~tltchlng ouol~ tog~th~r. ~h~
publlsh~d prlor n~t llt~r~tur~ rly ~iaalo~s ~h~ pr~alllng pre~aron~4 o~ ng ~tit~hi~g to pr~Jxo l~ag ~llts~ ~nd th~a lik~.
1~ ~o~ ~x~mple, U.~ PAt~n~ 3,4~2,602 ~l1OC1O~Q~ a bag ~lltar for ~ gA~ ing app~r~tuæ. ~hs ~g er ls ~o~med o~ ~llt~r ~ateri~l ~h~t~, ~uoh gla~s ~lb0~ l~ye~g, whioh ~r~ ~'clt~h~d tog~3~her ~o a~ to compr~ao tho ~llt~ materlal ~h~Qt~ and ~or~
15 sub~t~ntlall~f alr-t~gh~ m~. A~ ~n ~ rnativ~, in~t~a~ o~ ~titchlng ~ qdge~ o~ th~ ~llt~r ~nateriAl ~heets togeth~r, ~h~ ~dge~ may ~e glu~d or h~a~ ale~ tog~th~r .
~lmll~rly, U. 8. Pat~n~ 4, ~59, ~4~ dlaclos 20 ms~h~d o~ n~akin~ er ~o~:X, wh~r~ln ~h~
p:ro~ ~ct~n~ ~id~ o~ a p~n~l o~ two l~av~ old~d back over ~h~ ~re~ ~lae an~ the ~ld~ e s~wn tog~th~r to ~orm a tubo~
Tharo remaina, ~h~efor~, ~ n~d ~or ~ ~g ~5 ~ilter wl'ch ~m~ eon~truc~l3d ~n ~u~h a ~ann~r ~o not ~ llol,? the ~luid bQing ~llte~d to b~p~ the ~llter me~lum by way o~ thQ ~e~m~, whll~ ~t th~ ~Am~
provlding ~or ~ ~ood meah~ni~l bond at the b~g ~ilter ~a~. Xhe prs~ent ~nv~n~i4n pro~tld~ ~u~h ~
3 0 b~g ~il'c~r .

It 1~ ~n o~ Or th~ p~ 3nt ~hven~ion ~o providq a bag :~llt~r ~r~ red ~ro~ at l~ t on~
~hes~ o~ ce~ me~lu~, pr~r~l~ly ~ high dlr~

, :

J~N 31 '92 15-~2 202 LEYDIG UO}T M P.~6 2060~3~

cAp~aity ~lltor ~odiu~n~ which ha~ b~n ~O~IQ~ into A
bag aon~ ra~lon ~y ~oinln~ taqe~h~r por~lonq o~
tho ~lltQr m~dlum ln a way whlch provld~ ~or a goo~
~hAnioAl bond without provlding ~luld 1~3cago 5 pathway~
nothor ob~ ~c~ o~ thn pras~n~ lnvention to prov~d~ a motho~ o~ prop~rlng ~ bag ~lt~r hav~lng ~a~n~ wb~ch hav~ A hlgh ~ch~n~cAl ~t2~eng~h bu~
nov~r~ol~s~ ~o not pr~ a ~lu~ a~cag~ pa'chway~
~ e ~nd ot:h~r ob~ oqt~ ~n~ ad~ntAg~s o~ ~his lnventlon, a~ wall a~ ~dd~an~l in~ran~vQ Pe2tura~, wlll booom3 ~p~ar~nt ~rom ~h~ d~rlption of th~
p~essnt ln~v~ntion ~ovld~ herein.
~ho ~ro~Qnt lnYsnt10n ~on~rn~ a b~g ~llt~r lS aompr~lng ~ laas~ on~ ~he~1: o~ n ~llter madium ~orme~ ~nto A bag ~on~lgurati~n with ~n opQning, an n#1d~ ~r~aa~, an outslde ~ur~e, ~na at l~a~é ~n~
~e~n ~o~d at ad~oln~n~ r m~diu~u po~t~on~
wh~ch hAV~ bzon ~awn tog~th~r. ~h~ o~am~ o~ th~ ~aq ~0 ~ e~ a~led wl~h a th~o~pla~ t~ that h~
b~en ~ d ~o th~ el.d~o~nln~ cer ~edium portlon~. For example, the ~aam~ may b~ oovsr~ on at lea~t on~ ~id~, ~uc:h ~ the outsi~o ~ur~c~, wlth th~ heat ~e~led thæx~o~ tla ~ape. Al~ern~ ely ~5 or ln aa~ltion, th~ ther~oplR~lc tap~ may b~ ~n 0a1~ ~e~ or example, b~tween t~e ~d~oin$ns~
E ~ zl, Eaortlon~
Th~ ~e~ent lnv~n~iort al~o ~orl~emylate~ ~
metho~ o~ prepnxlng ~u4h b~g ~lt~ by ~Xisl~ o.t 30 l~aa~ on~ ~h~t o~ cer ~ um, ~itchlng ~ er ~dlum po~tlGn~ tog~thor l:o forla ~ b~g with ~n opon~llg, ~n ln~d~ ~ur~a~e, ~n ~-at~ld~ ~u~ac~, a~d ~t l~t on~ ~am ~ormæ~ at aa~oinlng ~ilter n~a~ium port~on~ whlch h~Y~3 be~ 5ewn togeth~r, ~ont~ctinSJ
35 thQ ~nm~ wLth ~ ~eh~m~ t1~ tape, ~nd th~n he~k-40006 - ~ -J~lN 31 'g2 15:133 202 LEYD1~3 UI~IT 11 P,07 2~60430 oQ~llng tho therT~oz~ t~a tapo to the ~d~olnlng ~lt~2 medl1l~ po~tlons.

~h~ pr4~0nt lnvontive bag ~lt~r oo~priaea nt 5 l~a3t orle Bh~et o~ a ~lltor modlum ~or~d lnto a bAg con~lgurA~l~n with an op~nlng, ~n lnsid~ ~u~aa~, an out~id6 sur~a~o, ~nd at 1~ one ~e~ ~ormad ~t a~olnln~ ~llter portion~ whi~h h~v~ b~an aewn together~ ~h~ ~a~m~ o~ ~h~ bag ~ll'cer ar~ seal~
10 w~th a thor~opla~tic tapa ~ha1: ha~ b~n hQat-~aled to th~ ~d~oin~ng ~ ax me~lu~ por~ion~0 ~ he pr~ent lnY~n~lve me1;hod o~ prep~rlng ~uch bas~ ~iltora lnvolY~aa takl~ a~ l~aot or,e ahe~t o~ a ~ilter m~dlum, ~tltahlng ~ r ~dium por'clon~
1~ tos~ hor to ~or~ A bag with ~n op~nlng, an lnsld~
~urfaa~ an out~id~ ~ur~ce, an~ ~t l~aot on~ ~am ~orm~d at ~d~o~n~ng ~ll'c~r ~d~u~ portlon~ ~h~h hava b~en ~own toç~athor, contsc~ g t~a tlOA~ W'l~:h a thQ~llOp~ tAE;~el, ~nd th~n h~at-~al~ng the~
~0 th~rmopl~stl~ t~p~ to th~ ad~oinlng ~ ar m~iu~ -po2-tiona.
~ h~ ~ag ~llt~r m~y 1~ o~ any ~uitab~o ~on~l~ur~tion ~a~d ~ize~ ~onventional ba~ ~llte~
ar~ 2~0ughly ~yllndria~l in ohap~ Rnd ~a~e ~Yail*blo as ~In s~z~a o~ 4 ~n~ ~ ter by g ~n~ ngth ~n~ 4 lnch dl~met~r hy lS l~h l~ngth~
$1ter me~ium ~ b~ ~ny ~ult~bl~ r shQet ~a~t~rl~l whic:h can b~ n~ ho~t~oo~l~d w~th ~ ~ul~le thes~opl~8tio t~pa~ EIow~
30 alt~ough ~he ~ilter m~aium ~n~y ~o~prl~e a lower gxa~ lt~r m~ter~al, th~ rllte~ ~dl~
pr-~r~b~Ly a high dirt ~pa~lty ~llt~r ~Rlu~o Mo~t pr~ar~bly o~ polypropylens. ~ho ~ r~d high dlrt ca~llc~ty ~ r me~ ompri~ a m~ blown 4~0~6 - 4 --:;
, .

-' J~N 31 '92 15:04 202 LEYD}G UOIT M P.0~
2~6~0 fibrou~ wsb o~ polyprepy~na ~lb~r~ in~o~wlnod an~l lay~rqd on ~ porou~ polypro~ylenQ ~ub~'crat-, euah a~
1~ u-e~ ln tho Pro~ g filter~ availa~l~ fr~m Pall Corpo~tlon (Ol~n Cov~ w York) ~ho po~lty of the flltar ~a~dlum o~ the bag ~ilt~r ~ay bo Any~ d~lllr~d v~lue~ q!h~ ba~ ~lt~r pr~erably ha~ ~ tapere~ or ~radod. ~orn etruo~ur6 with dear~a~l~ng per~ r~ ~e ~n~ide aur~ce o~
I;he baçJ ~ilker to the out~de ~urfa~e o~ th~l3 b~g ~0 Pilt~r (whioh will b~ ~he u~ual d~r6lot40n o~
tratlon ~low~.
~h~ b~g ~ilt~r m4y ~omprl~ o~har lay~r~ ~n a~tion to th~ r sheat mat~rlal, ~uch ~8 an inne~ l~no~ ~n~ out-r wrap of ~ non-wo~en m~t~ri~
~uah a~ o~ polypropyl~n~.
bag ~ er may bf~ ~or~d ~rom oT~e or ~aore ~h~e~c- o~ ~lter madi~ c ~h~ numb~r o~ ~h~st~
o~pioy~d wlll d~pen~ in p~t upon ~he ultim*ke ~hA}?~
o~ th~ bag ~ r and lt~ u~ mo~t ln~'cAncs~, bag ~ilter can b~ pr~par~d wlth o~ly on~ o~ ~wo r~lt~r m~dlu~ ab~ whioh ~rill do~i~ably ~nin~
th~ ext~nt o~ seam~. MOB~ pr~ bly, the bag ar ~o co~ cruct~ r~m ~ aingl~ ~hee~ o~ er madium, ~rQby ~e~ultl~g in ~ho ~xlatoncs o~ only ~5 ~lngl~ ~am ~oinin~ ~ho ~d~eo o~ t~ ~ho~ o a~ ~o l~a~ an op~n ~n~. In ~11 c~s, th~ oYer~ll ohllp~
c~ th~ b~g ~llt~r ~houl~ uoh tha~ a ~3~rt~ul~r or ar~a o~ a ~ not ~u~ t~d ~o ~ d atr~a~o 'ch~ough u~o th~t WQU1d IIOatl:~OY th~ int~r~'cy 33 o~ th~ ~eam.
~hs~ ~At~rl~ , an~ n~e o~ the thr~d to ~oln ~lt~r m~dlu~ po~tlon~ to ~orm the ~llt~k d~p~n~o upon t~e ~il1;~r ~di~m, ~h~ othar mat~riAl0 whlch m~y ~a la~d t~ ~orm th~ b~g ~llt~r, 3~ And ~h~ ultiraa~ uo~ o~ tho ba~0 ~h~ th~

40~06 o 5 O

,. ' ,, -.

JRN 3 1 ' 92 1 5: 05 202 LEY~ I G IJO I T M P . 09 2~04~

pr~rably 1~ o~ ~h~ m~ mat~rl~ th~ ~ilt~
m~lu~, e.g., polypro~y~n~
~h~ n~r of ~ltoh~/lnch ua61d ~o ~oln th~
~llt~r mQ~lu~ p~rt~on~ o~ the b~g ~ er wlll v~ry wi~ tho ~llter ~edium, the nu~ o:~ layer~ o~
~llt~r ~nsdlum, the thr~ad, th~ t;yp~ o~ ~ltching, ~n~ th~ ulti~t~ u~o o~ ~h~ ba~ Pilt~r. I~ 1~
ifflportant tl~t ~u~lalsmt ~'cltch~ bo ar~loysd to ~nou~e ~n ~e~t~ ~ch~n~cal bond bet~s~ll ad~o~n~
~llt~r ~dllam portion~, whll~, howev$r, en~uring that the numb~c o~ ~itc:h~/inah 1~ not ouoh ~hat ths ~tltçh~n~ r~ul~c~ ln th~ pQr~or~tlon ~r w~ak~a~s~
in1;~grlty o~ 'ehQ 1tllt~r ~di~m.
~he ~nnor ~n which th~ ~a~ on th~ b~g ~llt~r e~m may be v~rlQd. For ex~fflplo, th~ ~a~ may ~o straight-~tltch~d, wl~h ~ binder ~tr~p pr~er~bly ln~ert~ w~en th~ dg~ll o~ ~ho ~llt~r m~dium pr~or to ~ewin~ th~ ~ea~, or the ~am may be o~,rRr-~ti~Ghad~ When u~d, th~ bind0r atrip i~ ~r~e~a}~ly ~o o~ O ~m~ typ~ oS~ ma~orlell a~ the i~llt~r m~aium and/or tha:oad, ~.g., poly3~ro~ylen~
~h~ ~am on the bag ~llt~r 1~ ~aal~d wi$h th~rraopla~tlc ~i!lp2. ~ny ~uit~ble tho~pl~-tlc 1:apQ
~ay ~o~ u~d, prQ~e~ly a th~rmopl~tio t~ wh~h ~5 ~a~ a m~ltln~ teJnpexature low~ than ~ ltlng ~m~3~ratur~ o~ ~h~ ~lit~r sn4di~ an~/or thrlaad o~
~h~ g ~llt~r and. whicb will p~o~ uitA~
~eal w~th ~ho Ad~oln~ dtum po~tion~ In th~ ~a~ ln whl~h ~ p~lypropyl~ne ~llt~ m~dium lo u~â ln t~e ~or~atlon o~ ~he ba~ ~lt~r~ th~
th~ pl~tla ~pe 1~ prer~re~bl~f a poly~ropyl~ne çopolymor ha~ng A Jn~l~ing ~emp~ratllrs b~low ~h~t o~
polyE~ropyl~n~ .g~, ~ p~lypropylena-poly~thylon~
co~olym~r.
I~ ~hould b~ X~pt in 7~nd t~a~ th~ ~hoi~ oæ

40006 - 6 ~

, ~

JRN 31 ' 92 15: 05 ~2 LEYDIG UOIT 1~ P. 1~
2~6~3~

th~r~oplaetlc tap~ will dop~nd ln ~r~ upon the ~ount o~ h~at and pr~our~3 th~t cnn b~ pllo~ t:o tho th~opla~la ta~o on thR ~lt~r ma~llum t~
~f~ct thu ~t-o~l wlthout di~ruptlng th~
~nt~grlty o~ the bay ~ilt~r. ~h~ choiae o~
th~rmopl~la 't:A~ wlll d~p~nd on the ultlmate u~e o~ b~g ~lltor. ~or examplo, th~ bag ~ lt~r m~y ~ u~e~ un~r aon~it~n~ th~t may adver~ly A~ ot: th~ he~ l or~actod b~tw~orl th~
thermopla~tl~ ta~ ~n~ ~h~ ~e~ n whi~h c~e 1~ wlll ~ naa~ A~y ~o ~hoo~ An appropr~s th~r~oplas~a t~p~ to with~an~ ~he ~ntialp~te~
opQra~ing ~onditlon~.
Anoth~r con~d~ 10n 1T1 th~ cholo~ o~ the thormopla~ pe 1~ lt~ wl~th~ 'rhQ ~idth o ~h~
t~p~ mu~t b~ ~ui~clent tc e~e~tiv~ly oovo;r ~n~
~oal ~ho oAm.
~hs thsrmopl,~tlo ~ape mAy b~ appli~d ~o ~ith~r thQ ln~l~Q or ~he outold~ cur~a~e o~! ~he hag ~ er.
Al~ernatlvely~ or in Addltion, 'ch~ thermopl~k~c tapo m~ ~e ln~ Qtw~n the ~d~oinins~ rilt~
m~dlum po~tlon~ prlor to ~titchlng th~m to~th~r.
It 1~ pre~rr~d~ that th~ th~opla~ti~ t~p~ be~
~pplio~ to ~ov~r ~he ~eam oJ~ ~h~ out~l~Q ~u~i~aae o~
tha b~g ~lt~r. ~rh~ thor~opl~tlo tapo 1~
~r~ r po~it~ on~d ~uh that th~ dwAy b~t~qsn tho ~dga~ o~ th~ ~p~ ~urt~ morQ, ~a~
thermopl~tla tap~ pre~erably ~xt~nds ~yon~ th~
en~ , wh~r~ $blo OnG~ th~ th~rfflopl~tl~ ~ap~ h~ b6~n properly po~ltion~d wlth ~e~pe~t to ~ ~ea~, tho th~nopl~tlc l;:~pe i~ ~u~4ct~d 'co l~u~ isnt h~at ~nd pr~o~ur~ to ~ ct ~ h~at~ e~we~n ~he thermopl~tls: ~pe ~ hR a~oining ~llter ffl~liU~ -po~t~on~. Th~ amount o~ ho~L~ an~ pra~ r~qul~d JRN 31 '9~ 15:06 202 LEYDIG ~)DIT M P. Il 206~3~

to haat-~e~l th~ ~ape wlll ~pend ln pArt on the partlclllnr the~4pl~atic tAp~ an~ ~ilt~r m~dl~ uo~a ln th~ bag ~lltor. The a~pl1~d h~t an~ ~r~uro, o~ ~our~ hould not be oo ~at as to ~-troy thQ
5 inteqrity o~ tha !~ag ~ te~. In th~ pralrerrs~
o~bodi~ent wher~ln a ~olypropylQn~ copolym~r th~rmopl~tlc tape 1~ utlll~d, hot alr o~ out ~80-3~0 9F o~ ~o m~y J~ u~d t~ h~t thQ
ther~opl~t~o tA~4 on O~ bag ~ilter whi~h ie the~
10 pa~eA through rollær~ ko ~ at tho he~t-~æal .
A su~ta~l~ collar may be ~m onto th~ opsn end o~ the baq fllte~, w~th th~ r~ulting ~*~ bolng trea~Qd a~ de~cribed a~ov~ wlth r~eat to adgoining ~llt~ madiur~ portio~ h~ collar may b4 o~ any 15 suitablo materl~l, gan~r~l~ an ~ om~ric ao~pound o~ the ~am~ ~ner~ u~e~ in t~ t~r ms~ n ~ polypropylen~ ~llt~ edium 1~
uti~.lzed, th~n the aoll~ mater~al i~ pre~era~ly r~Ad~ o~ a l?~lypropyl~ne materlal, o.g,, n a o polypr4pylenQ ~opc~ r ~lah a~ 8~ntopr~n~
(Mo3~nto) .
I~ a ~ollar ~ chad to tha op~ nd o$` th~
bag $11t~r, c~rs ~houl~ ~ ox~rai~d 1~ ah~o~inq t~
~?la~tlc t~pa 8nd. the~ ~tlt~h l~n~ o en~u~e ~5 ~hat the aollax~ 1~ not ~r~or~ nd ~t the thermopl~la t~p~ e~lY~ly ho~t-~a l~ ~o both ~h~ er ~n~d~uln an~ th~ aolla~0 q?h~ bag ~llt~r mAnu~tu~e~ ln ~caor~n~;se w~t~
kh~ m~thod o~ th~ ~rR~nt inv~ntlon h~ ~ va~a~y o~
30 ~ult~bl~ ena w~. In pa~t~cul~r, ¢~ ba~ ~llter m~y be u~ o ~llter palnt~ and ~oating~, ~p~ai~lly wl~tRr-b~ p~l~t~ an~ prl3~er~, a~o~nlc~ ~, p~truohem~ o~ otlUGt~, watsr~ a~u~ou~
~olutionl~ ~nd ~usp~n~o~ nd th~ l~k~ ~rh~
35 utllity o~ th~ bag rllt~r ;L~ ~n no w~y l~l~'ced to I' . .
:; :

JRN 31 ' 92 15: 10 202 LEYDIG UOIT M P. ~12 2069~0 ~h~o~ u~ an~ in~lud~u mo~ u~ for c~nvQntion~
bAg ~ilt~r~.
~ ho ~llowing axa~npl~ ~er~re~ to further lllu~rat~ pre~en~ inv~n~ on bu~ 1~ no~ int~nde~
5 to llmit th~ pe o th~ invQnt~on~
&~L
~ lter bag~ o~ ~, 10 an~ 20 ~m por~ rAtlngo war~ pr~par~d ln ~oaor~anc~ th~ ~rs~n'c invention, ~loh o~ th~ bag ~llt~r~ wer~ con~truat~
~0 ln R f~m~lar mAnr~er. ~ ~ingl~ ~ho~ o ~ hiqh di~t c:~paci'cy polyp~opyl~n~ ~iltar m~ 4th A g~ad~
poro ~ ur~, tog~her wi~h non-wov~n, n~n-~lbsr ~h~ddlng, poly~ropyl~n~ lnn~r lln~r a~ out~r w~ap, w~ro ~titohed tog~1;her ~lnsl ~ polypropylene thr 15 (~izo #69) ~long tho ~o~ (aoll~r~ edge ln th~ rla~, ~rlo~ to ~ing ~titohe~ on the ~ nd botto~ ~n a ~lnglQ ~eam to ~orm a bag oonfigura~on o~ lisiZ6E~ 4 ~nch dl~st~r by S inch l~n~h ~n~ 4 lnch d~nm~t~r by 1~ lnch length.
~o ~ polypropylen~ bir~d~r ~ip w~o ~ ched ln~o the ~e~ms~ Tha bln~er ~t~ip wa~ 1 1/4 $nch4~ wide, with bo~h ~dg~ ~oldQd un~r to yi~ldl a 3J4-ln~h wid~ ~rlp.
~h~ bAg ~llt~r wa~ n~ld~-oll~ wlth a ~5 o~wing maohin~ u~lng a ~lng~ oh~ln ~itGh o~ 7 1 ~toha~/~nc:h ~lth ~ mlni~ thr~d ~en~ion oX 1 oz. and ~ ~ln~Toum bobl~in ~on~ion o~ ~ oz~, The ~lnlmum t~nolon~ on th~ ~wlng ~h~ne ar~
nec~ ry to en~uro tlght o~a~a. The n~o~l~ u~d ~0 dl~ not ~X~ 140 N~ lYa ~ 8 o~ khs ~h~t o~ llte~ lu~
w~r~ ch~d ~ alo~ pr~otlc~l to th~ ~g~ o~
tho blnd~ ~trip. ~o gap~ wQre allowe~ ln ~he ~am~
and all lay~r~ G0~ ng the bag $11t~r wer~
3 ~ aaptur~d in tha ~ hr~aa ~nd~ r~ aut ~00~ ~ ~

-:- . , JRN 31 '92 15: 11 2~2 LEYD~G VOIT M P. ~3 -2 ~ 3 ~

~pproxlm~t~ly 1/2 lnch long.
8~ne~ a coll~r WI~L8 to ~ at~ach~ o ~h8 o~?en ~nd o~ th~ baq ~llt~r, th~ dla~et~r o~ th~ bo.g ~llter wa- narro~ed to the dl~notclr o~ tha aol~hr, b~inr:ing 1-1/2 ~n~ho~ rroD~ open ~nd o~ th~ b~g ~ilt~r.
A~t~r s~w~ng and tri~ ng th~ thr~ad~ 'ch~ bag ~llter wa8 turn~d in~dl3-out. ~h9 :bottom ~nd 01~e ~ear~ w~r~ pu~h~ ou~ to provlde n w*ll-dq~lne~
10 co~tour to ~h~ b~., The ~ottom co~t~ur w~ ch~ck~
rOr 0y~u~0t;ry,.
~ aollar of Sant~p~n~- t~on~anto) wa~ att~h~
to th~l o~n ~nd o~ th~ b~g w~ a locX ~lt~h ~5-e Ohe~/~nCh) 1O~Ated ~/8 - lJ2 lnah ~ro~ ~ha 15 boétom o~ ~h~ oollar, with er~d~ o~ th~ ~tl~chlng pa~o~ng ~h other ~lxou~ nti~lly at ~ t 1/2 lnch. ~'c wao ~n~ured t~a~ th~ 3ti~c~ng wa~ not BO
ti~ht n~ 'co p~rrorat~ the collar. ~hr~n~ ~n~ ~t t~ collo.r wer~ ~rl~m~d t~ w~hln 1/~ in~h.
~h~o~lAstl~ 'cap~ ~3J4 ln~h w$~) o~
polypropylan~ copolyxll~r h~ ng a ~eltlng ~mp~ratur~
b~low ~hat o~ polypropylQno wa~ ~Ippl~L9t~ o the ~m ~n tll~ outold~ ~u~ace oP th~ ~g ~ltor. The th~r~opla~t~ p~ wa~ po~itl~n~d suoh tha~ th~ ~ap2 ~5 wa~ o~r~ter~d o~r~r th~ ~oa~ he t~p~ w~ ~her~ h~at-8~ s~ t:o tho ~e~a~ u~ng ~ot ~ia alld ~he~ pa~in~
thQ ba~ ~lte~ thro~agh roller3 ~he ~ a typ~ o~ ~hermopl~tl~ p~ w~
rly ~pplied tc~ ~h0 coll~r ~a~ on th~l ou~
~ur~ac~e o~ ~h~3 bag ~i~tQ~ us~ng hot aiLr ~nd rol~or~.
~h~ tApe ~o~er~d th~ ~oam aompl~t~l3r an~ a~hor~ to both ~h~ eoll~r ~rld ~ r ~g o~r th~ ~am. ~he thor~opl~ti~ 'cap~ on th~ collar ~a~ o~2:1 ~p~d the tapq and of ~ oido ~ th~ rilt~r mQalum.
3S ~h~ th~nopl~ia t~p~ a~her~ ly to , JI~N 31 'g2 15~ 02 LI~YDI~3 IJOIT t1 P.0'i 2~04~

ba~ ~llt~ thrcug~ou~ ngth and did not pe~l o~ wh~ u~d wlth ~he ~ing~ro. ~o araas o~
ov~rhoatln~ oi~ ~h~ ~llt~r ~e~lal sn~ th~ lc tApe, ~ldenco~ by ~mbrlt;'el~ nt ~d~acen~ ~o th~
S tap~a ~sm and by tr~n~luc~nt ~2~ea~ in th~ ~reA o~
th~ ~o~ wh~n ~xpoo~ to light, w~r~ o];~rtJ~91.
~Z
~ ~olypropyl~n o ~ro~ 0 ~g ~ilSer wa~
obt~ d ~om E~ o~por~l:lon ~Glan Cov~, Nqw Yo~k)~ own ~a~o o~ th~ bag ~ilta~ w~ro aov~ro~ wlth ~ thermopla~ t~pe ~omprl~lng olyp~opylsna ~opoly~r ~a~ing ~ ~o~ting ~mp~ratu~
l~wQr than that o~ polypropyl~ne, and ~bo th~rmopl~ti,c ~e~pe wa~ heat-~al~ to th~ er ~5 m~dium and ~o~lar o~ tha b~g ~ er by applicatlon o~ hot Air to the thermoplA~tl~ tap~, ~ollow~d l~y ~ppllc~tlon o~ mo~Qra~e pr~ur~ ~o the heate~
thQrmo~ tio ~pe. ~ pro~dJ thermopl~t~c tap~e~l~A s~wn b~g ~ilt~x WAII ~h~reby o~t~ln~.
Whil~ ~h~ lnv~ntlon ha~ }~nn ~Q~cr~b~ with ~pha~l~ u~on pr~orro~ nt~ wlll b~
o~viou~ to ~ho~ o~ ~dln~ry ~}cill in ~h~ ~rt ~h~t the pr~3~erre~ oag ~ r and ma~hoa o~ ~r~p~rirlg ~uch a b~ lk~ y ~)b varied. Tt 1~ in~ænd~d thA~ thz ~n~ention raay be ~ oth~rwis~ ~han a~ ~peoi~cnlly d~cr~b~d h~r~in. AoGo~dlng~ly~ thl~
invont~on lnc~lud~ all mo~ atlc7n~ ~nao~p~ d withln 1;h~ ~p~rl~ ~n~ ~op~3 o~ th~ Pollowlng ~l~im~.

4~06 ,

Claims (42)

1. A bag filter comprising at least one sheet of a filter medium formed into a configuration with an opening, an inside surface, an outside surfaces, and at least one seam formed at adjoining filter medium portions which have been sewn together with thread, wherein said are said with a thermoplastic tape that has been heat-sealed to the adjoining filter medium portions.

2. The bag filter of claim 1, wherein said seams are covered on at least one side with said themoplastic tape that has been heat-sealed to the adjoining filter medium portion.

3. The bag filer of claim 1 wherein said filter medium comprises a high dirt capacity medium.

4. The bag filter of claim 3, wherein said high dirt capacity filter medium comprises a substrate with entangled fibers deposited thereon.

5. The bag filter of claim 4, wherein said substrate and said entangled fibers are of the same material.

6. The bag filter of claim 5, wherein said high dirt capacity filter medium comprises polypropylene

7. The bag filter of claim 6, wherein said thread comprises polypropylene.

8. The bag filter of claim 7, wherein said thermoplastic tape comprises polypropylene-

9, The bag filter of claim 8, when said thermoplastic tape comprises a polypropylene copolymer having a melting temperature lower than the molting temperature of said filter medium

10. The bag filter of claimed 1, wherein said thermoplastic tape has a melting temperature lower than the melting temperature of said filter

11. The bag filter of claim 4, wherein said substrate forms the inside surface of said bag filter

12. The bag filter of claim 11, wherein said seams are covered on at least; the outside of said bag filter with said thermoplastic tape that has been heat-sealed to the adjoining filter medium portions.

13. The bag filter of claim 12, wherein seams are only covered on the outside of said bag filter with said thermoplastic tape that has been heat-sealed to the adjoining filter medium portions.

14. The bag filter of claim 1, wherein said thermoplastic tape is in said seams between the adjoining filter medium portions.

15. The bag filter of claim 1, wherein said bag filter further comprises a collar sewn onto the open end of said bag filter with at least one seam at the junction of said collar and said filter medium, wherein said seams are sealed with a thermoplastic tape that has been heat-sealed to the adjoining portions of said filter medium and said collar.

16. The bag filter of claim 15, wherein said collar comprises an elastomeric material.

17. The bag filter of claim 16, wherein said filter medium comprises a high dirt capacity filter medium of a polypropylene substrate with entangled polypropylene fibers deposited thereon and said collar comprises a polypropylene copolymer.

18. The bag filter of claim 18, wherein said high dirt capacity filter medium has a graded pore structure

19. The bag filter of claim 18, wherein said pores of said high dirt capacity filter medium increase from said inside surface to said outside surface of said bag filter

20. The bag filter of claim 4, wherein said bag filter further comprises a binder strip between adjoining filter medium portions.

21. The filter bag of claim 20, wherein said binder strip is polypropylene.

22. The method of preparing a bag filter comprising stitching portions of at least one sheet of a filter medium together to form a bag with an opening, an inside surface, to outside surface, and at least one seam formed at adjoining filter medium portions which have been sewn together, contacting said with a thermoplastic tape and then heat-sealing said thermoplastic tape to the adjoining filter medium portions.

23. The method of claim 22 wherein contacting said seams with a thermoplastic tape includes covering at least one side of said seams with said thermoplastic tape.

24. The method of claim 22, wherein said filter medium comprises a high dirt capacity filter

25. The method of claim 24, wherein said high dirt capacity filter medium comprises a substrate with entangled fibers deposited thereon.

26. The method of claim 25, wherein said substrate and said entangled fibers are of the same material.

27. The method of claim 26, where said high dirt capacity filter medium comprises polypropylene.

28. The method of claim 27, wherein said.
thread comprises polypropylene.

29. The method of claim 28, wherein said.
thermoplastic taps comprises polypropylene.

30. The method of claim 29, wherein said thermoplastic tape comprises a polypropylene copolymer having a melting temperature lower than the melting temperature of said filter medium.

31. The method of claim 22, wherein said thermoplastic tape has a melting temperature lower than the melting temperature of said filter medium.

32. The method of claim 25, wherein said substrate forms the inside surface of said bag filter.

33. The method of claim 32, wherein said seams are covered on at least the outside of said bag filter with said thermoplastic tape and said thermoplastic tape is heat-sealed to the adjoining filter medium portions.

34. The method of claim 33, wherein said seams are only covered on the outside of said bag filter with said thermoplastic tape and said thermoplastic tape is heat-sealed to the adjoining filter medium portions.

35. The method of claim 22, wherein said thermoplastic tape is positioned in said seams between the adjoining filter medium portions prior to stitching said adjoining filter medium portions together.

36. The method of claim 22, wherein said method further comprises sewing a collar onto the open end of said bag filter thereby forming at least one seam at the junction of said collar and said filter medium, contacting said collar seams with a thermoplastic tape, and heat-sealing said thermoplastic tape to the adjoining portions of said filter medium and said collar.

37. The method of claim 36, wherein said collar comprises an elastomeric material.

38. The method of claim 36, wherein said filter medium comprises a high dirt capacity filter medium of a polypropylene substrate with entangled polypropylene fibers deposited thereon and said collar comprises a polypropylene copolymer.

39. The method of claim 24, wherein said high dirt capacity filter medium has a graded pore structure.

40. The method of claim 39, wherein aid pores of said high dirt capacity filter medium increase from said inside surface to said outside surface of said bag filter.

41. The method of claim 22, wherein said method further comprises positioning a binder strip between adjoining filter medium portions together and then stitching said binder strip together with said adjoining filter medium portions.

42. The method of claim 41, wherein said binder strip is polypropylene.