CA1159317A - Process and apparatus for contacting a powder with a fibrous web - Google Patents
Process and apparatus for contacting a powder with a fibrous webInfo
- Publication number
- CA1159317A CA1159317A CA000358724A CA358724A CA1159317A CA 1159317 A CA1159317 A CA 1159317A CA 000358724 A CA000358724 A CA 000358724A CA 358724 A CA358724 A CA 358724A CA 1159317 A CA1159317 A CA 1159317A
- Authority
- CA
- Canada
- Prior art keywords
- web
- powder
- air
- moving
- enclosure
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- D—TEXTILES; PAPER
- D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
- D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
- D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
- D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
- D04H1/58—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties by applying, incorporating or activating chemical or thermoplastic bonding agents, e.g. adhesives
- D04H1/60—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties by applying, incorporating or activating chemical or thermoplastic bonding agents, e.g. adhesives the bonding agent being applied in dry state, e.g. thermo-activatable agents in solid or molten state, and heat being applied subsequently
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- Engineering & Computer Science (AREA)
- Textile Engineering (AREA)
- Nonwoven Fabrics (AREA)
Abstract
PROCESS AND APPARATUS FOR CONTACTING A
POWDER WITH A FIBROUS WEB
Abstract of the Disclosure A process for contacting a moving fibrous web with a powder. The process comprises the steps of:
I. passing a mixture of powder and air through the moving fibrous web;
II. reversing the direction of movement of the fibrous web; and then III. passing a mixture of powder and air through the moving fibrous web in a direction opposite to that of Step I.
An apparatus comprising an air-tight enclosure;
means for maintaining subatmospheric pressure within the enclosure; means for passing a fibrous web through the enclosure; and means within the enclosure for passing a mixture of powder and air through the moving fibrous web.
POWDER WITH A FIBROUS WEB
Abstract of the Disclosure A process for contacting a moving fibrous web with a powder. The process comprises the steps of:
I. passing a mixture of powder and air through the moving fibrous web;
II. reversing the direction of movement of the fibrous web; and then III. passing a mixture of powder and air through the moving fibrous web in a direction opposite to that of Step I.
An apparatus comprising an air-tight enclosure;
means for maintaining subatmospheric pressure within the enclosure; means for passing a fibrous web through the enclosure; and means within the enclosure for passing a mixture of powder and air through the moving fibrous web.
Description
~S9317 PROCESS AND APPAR~TUS FOR CONTACTING
POWDER I~ITH A FIBROUS ~:B
Disclosure It is known to apply dry powders to webs during the formation of bat~s ~or various purposes. For example, dry powdered boric acid is fre~uently applied to garnett webs of cotton which are subsequently cross laid or cross- `~
lapped on a mo~ing conveyor ~o fo~m a batt, said batt having a certain degree of fire resistance resulting rom ~he application of the boric acid powder and its mixture with the cotton in the web ana the battO
Other well-known processe~ involve ~he applica-tion to the web o~ either ~hermo-se~ing resins or thermo-lS plastic resins in dry powdered ~orm, generally but notnecessarily ollowed by cross-lapping the web to form a batt which is subsequen~ly heated. In the case o~ thermo-s~tting resins the makerial stiffens the fibers in the batt structure as the thermo-setting resin goes through the process of melting and hardening. A limited amount o~ bonding between fibers may occur with these resins.
Thermo-plastic resins, on the other hand, generally flow ; ~o a greater extent on the fiber surfaces as the ba~t is heated, so ~hat the melted resin ~o~ms more sites for 2S inter-fiber bonding. The s~rength anc~ unctional utilit~
of the bonds thus oxmed dep~nd on the characteris~ics o~ the the~mo-plastic resin, including its flow proper~ies, its melting point, its tackiness or s~ickiness in molten ~orm, and the tougl1ness o~ the resin bond when it has been coolea agai.n to a temperature below i~s sof~ening point.
~ arlous methods o~ appl~ing dr~ powdered materi-al ~ ko ~ibrou~ webs h~v~ b~n di~closed in paten~s and pu~licationsl and s~veral o~ these me~h~d~ have ~ouncl wicl~pr~ad commeraial appliaa~ion. Fo.r ~xc~lplo, one o 35 tilG mosk wid~l~ us~d ~k~pe~ o~ powder appl.tca~ors is the s~rewqr, whl~h is ~ss~ntiall~ a hopper cJener~ havln~
.
S~317 a more~or-less V-shaped cross section. At ~he bottom of khe "V" various means are used to meter out the required quantity of powder which thereafter falls by gravity onto the surface of the f"ibrous web wh~ch passes continuously beneath the strewer. Knurled rolls~ doctor-blades, com-~inations o~ br~shes and rolls, series of brushes, per-forated rolls and belts, and other d~vices are used to release the desired ~uantity of powdered material ~rom the strewer hopper. A~ the same time ~arious devices may be needed to keep the powdered material uniformly suspended and distributed within the strewer hopper itself. Several types of paddles are sometimes emplo~ed, ~ibrators of various types are used, and in some cases the powdered material is even fluidized ~o ensure ade~ua~e flow through the metering device.
Strewers have many disadvantages. The strewer width must conform closely to the width o~ the fiber web in order to avoid either a loss of powder if the strewex is ~7ider than the web, or to avoi~ areas of web which are untreated if the strewer is not as wide as the web.
Metering a precise amount of powdered material is dif- -ficult, as the many ~arieties of strewer will attest.
Among the major problems is the fact that the powder which is dropped by gravit~ tend~ to remain on the top of the web, khus leaving fibers which are untreated. With cer-tain ~unctional powders this leaves part o the ha~, non-~unctional or unpro~ec~ed, or in the case of bonding re,sins, ~i~es rise to the formation o~ a batt which has characteristia laminar quali~ies because layers which are bonded together b~ the resin carried on one side of the w~b alternate with layers between which there is little or no resin. ~nother di~advankage o~ strewers is that l~he~ ~nd ~o produce axa~ssive amoun~s o~ powder du~ in kll~ air wh~c~ is di~:~.icul~ ~o con~ol, A :Eux~h~r d.i~-3S ~iaul~ with ~r~w~rs is ~ha~ ~h~ powder must be me~r~clin~o the 5trewer to maintain some reasonabl~r aonstarlt ~ 93~ 7 supply of makerial while at the same time it must be metered out to ensure application of the proper amount o material onto ~he fibrous web. A double metering system has been employed in an e~fort to overcome this disad-S vantage, however such a;system has ~he additional problemof coordinating the rates of the two systems.
Qther methods of applying dry powdered ma~erials to fibrous webs produced by carding or garnettlng overcome some of the disadvantages of the strewer but introduce other problems w~ich ma~ include non-uniformity o appli-cation, low efficiency o~ powder usage, excess dust in the air, and incomplete coverage of the fiber web assembly.
Because o~ their shortcomings few, if an~, of these methods have found widespread comme~cial application~
Examples of prior art processes are describecl for example in Fleissner U.S. Patent 3,765,971 and in Buck et al. U.S. Pakent 3,993,518, hereinafter referred ko simply as "Buck".
Accordingly, i~ i~ an object of the present invention to provide an improved dr~ process for contacting a powder with a web and or producing a batt which processes are substantially free o~ ths disadvantages o~
the prior art.
~nother objeck is to provide a method for the in~nate uniform lmpregnation of the 1bers with the powclered material.
Still another object is to provide a method wherein the tendency of the la~ers o the web ~o form dis~inct laminations in the finished batt is eliminated, or minimized.
Ye~ another object is ko provida an improved rn~hod wherei.~ an even ~reatment oP powder over khe en~:irc wid~h o:E t~ ihrous w~b .i~ achieved.
S~ill a~o~h~r obj~ is ~O provide an ~mprovecl 3S m'e~hod whe.reln virtually ~ompleto aontai~nenk ~nd control ,~ o~ powd~ dust i.s achieved.
. . .
5~3317 Yet another objec~: is to provide an improv~d method whexein essentially lOOn~ efEiciency in the use of khe powdex is attained.
Still ano~her object i5 to provide an improved ap~aratus lor intimately contacting a powcler with a web~
Yet another object is to provide an improved ap~aratus for practicing the process of the present invention.
~ dditional objects and advanta~es of the present invention will be apparent to those skilled in the art by reference to the followin~ detailed description and to th~ drawings which are briefly described below.
Figure 1 is an elevation view o~ an apparatus suitable for practicing the process of the present inv~n-tion.
Fi~ure 2 is a plan view of the apparatus ofFigure 1.
Figure 3 is a sectional view taken along Line 3-3 of Figure 2.
Figure 4 is an enlarged sectional view taken along Line 4-4 of Figure 2.
Figure 5 is a secti~nal view t~ken along Line 5-5 of FicJure 4 which is identical to ~ine 5-5 of Figure 1.
Fi~ure 6 is a schematic, exploded view of the powder distribution wand which i5 also shown in Fi~ure 5~
Figure 7 shows a powder distribution means that is an alternative ~o the wand of Fiyure ~
Figure 8 shows a hag filter and is a sectional ~iew taken along Line 8-8 of Figure 4.
Figure 9 shows the ~oraminous belt with a web thereon and i~ an enlar~ed sectional view taken alon~
Line 9-3 o~ Figure ~.
'r~l~ abov~ ancl okhex objc-3a~.s axe accompll~hecl ~c~orclin~ ~o the pr~n~ inv~n~iorl b~ providin~ a proc~s~
~or lntima~el~ contac~irlg a ~ow~er with a movincJ ~ibxou5 web comprisi.ng the st~ps o~:
~ . c~ownwa~dly p~sing a mixtur~ Oe po~rder ancl air t~lrough the movirlg ~ihrou~ WC3~;
- - - -5~13~7 II. reversing the direction o movement o~ the fibrous web; and then III. passing a mixture of p~der and air through the moving ihrous w~b in a direction opposite to that 5 of Step I.
According to another aspect of the present inven-tion there is provided an apparatus for intimately con-tactin~ a movin~ ibrous web with a powder wherein the apparatus comprises~
A. a substantially air-tight ~nclosure;
B. means for maintaining subatmospheric pressure within the enclosure;
C. means for passing a fibrous moving web into the enclosure;
L5 D. means within th~ enclosure ~or passi.ng a first mixtur~ o powder and air through the moving ~ibrous web;
E. means ~or reversing the direction of mover,~ent o~ the fibrous web;
F. means or passing a second mixture o~
powder and air through the moving fibrous web in a direction opposit~ to the direction o~ the first mi~ture; and G~ means or passing the fibrous web ~rom the ~nclosure~
Th~ apparatus of the pre~ent invention includes an enclosure in which the fibrous web is ~reated with powder. Generally this enclosllre is located immediatel~
after the dofer of a garnett or cardiny machine, and ahead of the cross-lapping apparatus which depos~ts khe web on the :Eloor apron. O~ course the apparatus ma~ be usecl e~uall~ well to treat webs which are not cross-~.a~Qcl hu~ ~Ihi.ch cc>n~inue ~rom the a~paratus :in a ~andem clr~an~em~n~ he~ ~or ~ur-~r treal~ment, suGh as h~atin~
:in an oven, ox for paal~acJing ~n rolls or other ~orms~
l`he ~nclosure in which the web is treak~d prefer~bly has onl~ wo openings, on~ through which ~he weh enters, and a second .~rom whi.ch ik exi~ a~t~3x krcak-me.n t . Tha~a o~enill~Ts are g~nerally, althou~ nok neces-sarily, formed by pairs of rolls betwe~n which kha ~ibrous 3~
web passes. The po~Jc~ered material to be applied to the weh enters the enclosure in one or moxe enclosed pipes.
Air ls e~-hausted from the enclosure by a fan operating through filters as ~escribed below.
No convevor ~or the web enters the enclosure, or e~its from it. The elimination of such conveyors reduces the openings into the enclosure, and also eliminates the possibilit~ that ~he conveyors themselves will carr~ powdered material out o the enclosure. In the ap~aratus of the present invenkion the fibrous web simply leaves a conveyor ar.d itself enters the appli~ator enclosure. In the same way, it leaves an internal conveyor at a point within the enclosuxe before exitin~
the enclosure bètween a pair of rolls. There are, of course conveyors for the fibrous web ~hich are within the applicator enclosure, but these conveyors remain en~
tirely inside the enclosure so that they neithex require entrance or exit ports, nor can they carry any powdered material out o the enclosure.
The entire enclosure is maintained under nega-tive pressure. Thus there is a tendency for air to enter the applicator enclosure along with the fibrous web at the entrance port and even or some air to enter the en-closure around or bet~reen the rolls at the exit port.
The maintenance of a signi~icant ne~ative pressure within the applicator enclosure prevents the dust or powdered material from escapincJ into khe area outside the enclo-sure. Generall~ the negative pressure within the enclosure is mainkained b~ employing an exhaust fan which draws air throu~h a series of bag filters which axe contained ~Jithin the enclosure. Alternative arrarlcJernents such as cyclone~, or c~clon~s accompaniecl b~ eill~ers, may al~o be use~ but ar~ le~9 pre eerred~
Wikhin t~ ~nclosure ~he ~ibrous web~ suppor~ecl 3~ in par~ ~y conveyors, ma]ces a~ leask one chancJe in cli~
rec~ion. 'I;~his ~rmi~ botll sides o~ khe web to b~ -~r~ate~
~1~9317 with the powdered material which is injected into an air stream which moves in a single downward direction. The drawings discussed below illustra~e an enclosure in which the web makes kwo changes o direction, but an S enclosure having a single change in direction may ac-complish the purposes described above. It will be noted that the powdered material passes through the web at least twice, from opposite sides of the web, but that the powdered material itself moves in a single downward direction.
Excess powder in the air is captured on the bag ilters or similar devices and redeposited on the web. In order that this redeposition be made in a uniform manner, generally the bag filter is placed within a separate chamber inside the main applicator enclosure so that when shaking or reverse~pulse air puffing removes the accu~ulated powder from the bags it falls within the separate chamber from which it is dispensed uniformly and evenly across the width of the web passing beneath by a suitable series o~ rolls and brushes, or combina-tions thereof, or alternatively by a suitable vibratoxy ~eeder. The powdered material itsel~ is introduced into the applicator enclosure suspended in a rapidl~ moving airstream contained in a suit~ble con~eyor pipe. The precise amount of powdered material needed for applica-tion to the fibrous web is metered into thi~ airstream by a sui~able means, such as a screw feeder or vibratory ~eeder and generally enters the airstream itself through a venturi device. After the powdered material has entered the applicator enclosure through the air pipe in which it is suspended, it is distributed across the width o~ the fiber web and literally blown through the web by a sui.~ahle di~ributing de~ice xe~erred to herein as a w~nd or dis~rlbu~or, se~eral examples o~ whiah are 35 ;illuskr~t~d ix~ l~he drawing~ h~r~:in. A~ leasl~ one wand or powde dlstributor i~ used. When a single wand or powder 5g317 distributor is used, part o~ the powder being a~plied is blown com~letely through the web, thexeafter im~in~ing the weh a second time on the opposite face a~ter khe web has made a turn within the applicator enclosure. Gen-erallyr however, it is;preferable to emplo~ a second wandor powder distributox to assure that sufficient powdered material is applied to the second side and then it in turn also has an o~portunity to penetrate the entire web structure.
The excess powder which has passed through the eb from both sides is collected and redeposited once again on the fiber web to ensure its cvmplete and ~f-~icienk use in the process. In the configuration in which the web makes at least two changes o~ di.rection much of the powdered material simply falls onto the top of the fiber web as it makes its final pass within the appli-cator enclosure, after which it is carrie~ ~rom the en-closure with the exiting web. At least a part of this powdered material, after passing through the web at least twice, is picked up and circula~ed back to the bag filter through plenums on either side of the enclosure which collect that excess p~wder ~rom the bottom of the appli-cator enclosure. This recaptured powder is subse~uently redeposited into the top surface o~ the web ~rom the ba~
~iltar apparatus as described above.
~ 11 the conveyor belts which support and aarxy tlle web on its passage through the applicator enclosure are ~raminous and are of an open mesh type, permitting free ~assa~e of air and powder through both the web and the conve~or belt where this is necessar~ and desirable.
'rhU5 it i5 ~ossible to maintain a continuous ~low o~ air in on~ downward direation thxou~h the web and the hqlts, ~a~ dir~c~ion h~in~ ~oinciden~al wi~h the direction .in which th~ pow~er is in~ectqd into th~ wehs ~rom the wand~ or powcler distributors.
~55~3 ~7 Various rneans, including the use of compressed air fed through flexible hoses may be used to keep the powclered material sufficiently suspended in the bottom o the applicator e~closure so that it can be picked up i.n the return airstream:~hich 10ws thxough the side plenums or ducts to ~he bag filters a~ the top of the enclosure.
~ eferring now to the drawin~s and in particular to ~igures 1 and 2, there is shown an apparatus 10 useful for ~racticing the process o the present inven-tion. The apparatus 10 com~rises an opener or a garnett 11, an apparatus 12 for applying powder, a cross-la~ing mechanism 13 and, as shown in Figure 2, an oven 14, and cooler 15. The garnett 11 comprises an inlet 15 chute 18 adapted to feed bulk fibers to the rotating drum .s 19 of the garnett 11. The garnett 11 is also provided with a pluxality of tooth rolls 21, 22, 23, 24, 25 which, together with the teeth not shown on the drum 19, -take bul]c fibers 20 and convert them ko a web 31 which adheres to the drum 19. The web 31 adherin~ to the drum 19 is transferred to the drum 28 where it is removed by a comb 29. The thin, planar web 31 that is now only between 1 and 100 fibers thick and is barely sel~-supporting entexs the apparatus 12 in a hori~ontally di.sposed posi~ion, where it is contacted with a ~owder as described moxe completely below.
The powder-treated web 39 then goes to the conve~or 41 and thence to the conve~or ~2. In a manner well known in axt, the lower end of the conve~or ~2 is attached to a traveller 43 which moves baclc and forth on a track 44. The conveyor 4~ is positioned above and a~ ri.~hk an~les to a conveyor ~5. The aonveyors ~2 and ~5 are ~cljusted such that ~he 3peed o~ ~he conve~or ~2 .~s ~everal ~ime~ ~a~r ~han ~he ~pe~3d of kh~ conve~or ~5. ~ v:lrkue o~ ~hi.s arrangemen~, khe web 39 is aross-la~e.d hack ancl ~orth on the conveyor ~S thus formin~
l~ ~L5~3 ~7 --10-- , an unheat-treated batt 47. The unheat-treated batt 47 passes on~o a foraminous belt 50 (see Fi~ure 3) which passes into the oven 14~ As shown in Figure 3, the oven 1~ is provided with ~eaking ~eans 52 which can be ther-mostat:icall~ controlled by a thermostat 53. The oven14 is also provided with air circulating means not shown that causes the air to circulate in the direction shown by the arrows 55 and 56. Ba~fles not shown are provided at either side of the batt to insure that the air cir-culates through, rather than around, the batt. The~ebaffles are adjustable, to accomodate batts of different widths.
After leaving the oven, the batt 47 then enters an enclvsed transition chamber not shown betw~en the oven 14 and cooler 15, where it pas~es from the belt 50 of the oven and entexs between an upper ~or~`nous belt 49 and a lower foraminous belt not shown which compresses the batt 47~ The upper belt 49 can be raised or lowered by means not shown, to control the thickness of the final batt. While held and compressed between the two belts, the batt 47 enters a cooler 15~ In the cooler 15, cool air is moved by an air circulatin~ means not shvwn through the batt 47 and the two foraminous belts. In this manner, the resin is ~rozen and the batt 47 assumes the ~hickness it had while compre~ed between the two belts.
The resultant product is the ~inal heat-treated ba~t.
Refexring now to Figures 4 and 5, there is shown in sectional view the apparatus 12 for applying powder to the web 31. The apparatus 12 has an air-tight enclosure 60. The air-tight ~nclosure 60 divides ~he appara~us 12 into a low~r ~one 62, an intermediate æone 6 3, ancl an upper zone G ~ . :Cn ~he lower zon~3 G ~, I:hq we~ is con~ac~ wikh powd~r. ~n ~he in~ar~
35 medi~e xona 63, l:lle exces~ powder is collecked and :Eed baclc onta th~ web 31. In kha upper zone 6 ~ air is remove~l by a ~an fi~ drivan b~ a motor 67.
~lS~3~7 The lower zone 62 i~ provided with an entrance comprising an opening 70 to facilitate access of the web 31, and two rotating rolls 72, 73 adjacent to the open-in~ 70 which are provided with means (not shown) to cause them to rotat~ in the direction of the arrows as shown. Within the lowe~ zone 6~ is an endless conveyor 74 which moves around rollers 76, 77 each of which rotate around their respective axes in the direction o the arrows shown thereon. Balow the conveyor 74 is anoth~r endless conveyor 78 which moves around rollers 80, 81 in the direction of the arrows7shown. In the preferred embodiment depicted in Figure 4 the lower zone 62 is also pr~vided with a third endless conveyor 82 adapted to circula~e around rollers 83, 84. The lower zone 62 is provided with a powder distrihution wand 8~ positioned above the conveyor 74 and with a second pc~wder distribution wand 86 ' positioned above the con-veyor 78. The lower zone 6~ is provided with an exit opening 88 to permit egress o the web 39. Adjacent to and parallel to the opening 88 are two rolls 90, 91 rotating in the airection o~ the arrows as sh~wn. The bottom of the lower zone 62 is provided with inwardly sloping walls 92, 93 terminating in a central collectin~
well 9~. Within the well 94 is a stirrer 96 having Elexible outlet hose 98 which is adapted to receive air under pressure from a pipe 100 connected to a compressed air source not shown. Air leaving the stirrex 96 ~rom the hose 98 causes the stirrer 96 to rotate about the vertical portion of the pipe lO0.
The intermediate zone 63 is provided with a :Eirs~ lower wall 104 which slopes downwardly and inwardl~
~rom the ~orwarl wall 106 o~ th~ aix~ h~ enclo~ure G0.
h~ lntermediak~ xone ~3 is ~lso provid~d with a ~eaoncl :l~wcr wall lO~ wh~ch ~lopes downwardl~ and inwardly ~rom 3.'j tlle rea.r w~ll llO o~ the enclosure 60. rrh~ extren~e lowe~
encl o~ the wall 1~ and the extreme l~wer encl o~ th~ wall 3~7 108 define a slot over the first conveyor 7q in which rotates a roll 112. The surface of the roll 112 is grooved or knurled in order to permit powder to adhere ~hereto. Below the roll 112 is a cylindrical brush 114 ada~ted to brush the,~urface of the rvll 112 and remove powder therefrom. The roll 112 substantially fills the slot formed by the lower extremities of the walls lO~, 108.
The intermediate zone 63 is provided with an upper wall 116. Depending from the upper wall 116 are a series of bag filters 118, ll9, 120, 121~ 122, 123. The bag ilter 118 is provided with a compressed air pipe 124 terminating in a nozzle 126. The pipe 124 is provided with a valve 128 controlled by a timer 130. Each of the bag filters ll9, 120, 121, 122, 123 and other bag filters not numbered are also provided with sources o~ high pressure air similar to the pipe 124.
Referring now to Figure 5 it can be seen that the enclosure 60 is provided with an external plenum 13 in the form o~ a rectangular pipe 133 having a lower opening 134 in fluid communica~io~ with the bottom of the lower zone 62 and having an upper opening 136 in fluid communication with the intermediate zone 63.
The enclosure 60 is also provided with a second plenum 138 having a lower opening 140 and an upper opening 142 the purpose and ~unction oE which are more completel~
dascribed below.
Referring now to Figure 6 there is shown a powder m~tering and distribution apparatus 144 compris.ing a hopper 146 adapted ~o hold powder 148. The bottom o ~he hopper 146 is in communication wi~h a screw conveyor L50 adap~ed to be turned by a variable spaed motox 152.
'rha ~pe~d o~ ~he mo~or 15~ d~exmine~ ~hQ amoun~ o~ powd~r 154 leavin~ ~he ~nd o~ ~ha ~crew conveyor 150. I'he powd~r 3~ 15~ d~ops inko ~ second hopp~r 15~ wh:ich i~ up~traam o a vent~lr~ 15~ suppli~d with a ~ource o~ high pre.~ure air ~not shown) ~ia plp~ 160 ~exminating in nozxle 16~. The -- - ~
~L55D317 venturi 158 ensures thAt the powder 154 will be admixed with ~he air when the powder-air mixture 161 leaves the venturi 158 via the pipe 164. The pipe 164 i5 in fluid communication with t~e pipe 166 which in turn is in ~luid communication with the wand 86. As shown in Figure 6 the wand 86 has been ro~ated 90 to more clearly show its structure. However, the area transvers~ to flow of the powder-air mixture 161 continually decreases such that the amount o~ the air-powder mixture 161 leaving the firs t opening 168 is thei same as th~ amount o aix-powder mixture 161 leaving the last opening 170~ All structure shown in Figure 6 is in the priox art.
~eferring now to ~igure 7 there is shown an alternative pswder distribution apparatus 17~. The apparatus 172 comprises a pipe 17~ adapted to be in ~luid communication wi~h the pipe 164 of Figure 6. Attaahed to khe pipe 174 is a deflection plate 1~. The defleation plate 176 comprises a ~irst portion 17B substantially parallel to the direction of flow as shown by the arrow 181~ The plate 176 comprises a second portion 180 joined to the first portion 178 by an intermediate curved portion 182. Positioned on the second portion 180 is a V-shaped deflector 184 the vertex 186 of which i5 placed directly in line with the powder flow as shown by the arrow 181.
I~eferring now to Figure 3 r there is shown the bag filter 118 in an enlarged view. The bag ~ilter 118 comprises a first metal plate 188 provided with a plurality o~ holes such as the holes 190, 192~ The bag ~ilter 118 i5 provided with a second plate not shown parallel to the ~irst plate 188. A cloth bag 19~ is placed over and completel~ 3urxoun~ the ~lat~ 183 an~
~he pa~allel ~la~ no~ ~hown. ~c~ powdor aolleat3 on kh~ c~u1:~3id~ o~ ~h~ bag 1~4 and w:ill be hqld th~r~ b~ th~
di;~e~r~nce .in pres~ure on ~he ou~sid~ o~ the ba~ 19~ ~
compared to the pressure on ~he in~ide o~ th~ ba~ 19~.
IIowever kh.is pc>wder can be caus~d to be disloclgt~d lE
~ g31~
the air pressure on the inside o~ the bag 1~4 is tempo-rarily increased by a puff of high pressure air from the nozzle 126.
Referring ~ow to Figure 9 there is shown the roller 80 with its endless conv~yor 78 supporting the web 31.
The operation of the apparatus 12 is best under-.: stood by reerence to Figure 4. In operation the web 31 enters the air-tight enclosure 60 through the opening 70 and through the nip of the rolls 72, 73. Th0 web 31 then falls onto the conveyor 74 and, as it moves laterally, passes underneath the ~irst discharge o~
powder caused by the action o~ the brush 11~ against the roll 112. The web 31 now carried by the conveyor 74 passes underneath the wand 86 th~reby rece~ving a second dose of powder~ The web 31 is then ~urned downward and around on an axis perpendicular to the direction o move-ment of the web 31, until the web 31 is moving in a revexsed direction and passes onto the foraminous belt of conveyor 78~
Some of ~he powder issuing rom the wand 86 is retained on the web 31. A portion of the powder-air mixture passes through the web 31, ~hrough the upper portion o~ the conveyor 74 through the lower portion of the conveyor 74 an~ again contacts ~he web 31 while the web 31 is supported by the conve~or 78. As the web 31 suppor~ed by the conve~or 78 passes underneath the wand 86' a third dose of powder is given to the web 31~
Some of the powder issuing from the wand 86' is retained on the web 31~ However, a portion o~ the p~wder-air mix~ure passe~ through ~he web 31 thxough the upper portion ~ tha conveyor 78 and through ~he lowor por~ion o~ ~ha con~or 78 and ~hen a~aln con~acts the 3S web 31 wh:Lle ~he web 31 is supported on the upper portion o~ the conveyor 82~ The wab 31, whiah is now termed a powcler-~reatea we~ 3~, is aaxrled by ~he upp~r por~.ion 3~7 of the conveyor 82 and then passes through the nip of rolls 90, 91 and exits from the enclosure 60 throu~h the opening 88~
Air is removed from the enclosure 60 by the ~an 66. The fan 66 draw,s air from the upper ~one 64 of the enclosure 60, ~rom the inside o the bag ilters 118, 119 r 120, 121, lZ2 and 1~3~ and upward through the plenums 132 and 138. The fan 66 creates subatmospheric pressure within the enclosure 60 in general and in particular within the lower zone 62, the in~ermediate zone 63, and the upper æone 64 as shown by the li~uid level in the manometer 196. Since the enclosure 60 is under a subatmospheric pressure external air tends to leak into the enclosure 60 whereas dust and powder-laden air are prevented ~rom escaping. Air is supplied to the enclosure 60 as part of the air-powder mixture supplied by the wands 86, 86' and as part of the compressed air issuing from the hose g8 of the stirrer 96. Furthermore, air leaks in~o the enclosure 60 through the openings 70, 88.
However, a size of an 66 and dri~ing motor 67 are selected in order to remove all of the air that enters the enclosure 60 from any source whatsoever while still maintaining a subatmospheric pressure within the enclosure 60 as s~own by the manometer 196. The pre~erred subatmospheric pressure is between one half and five inches of water.
Another important aspect o~ the present inven-~ion is ~he internal ~low o~ powder ~nd o~ air. Powder is supplied to the web 31 by means o~ the wands 86, ~6'.
However the powder which drops to the bot~om of ~he lower zone 62 o~ ~he enclosure 60 encounters the inwardl~
slanting walls ~2, 93 and drops into the well ~4 where the powder is again entrained in air by means o~ the s~irrer 96. r~he ~an 66 drr~ws air ~rom ~he opening 136 as shown ;in ~igure 5 ~rom the plenum 132 and also ~rom 35 ~l~he W~ll 94 ~hrou~h ~he openlng 13~. Thl~ ensu~ tlla~
~lie ~en~ral :elow oE ai.r and powder i9 downward :Ln tho lc)wer zone 62 and is upward in the plenums 132, 13~ .
rrhe powdar-aix mis~ture is drawn to the ba~s 194 -16~ 93~7 (s~ Fi~3ure 8) ~.~hereupon the powcler s~ops on the outside of the ba~ and the air travels throug}- the ba~ 19~
through the upper zone 6~ of th~ enclosure 60 and from the enclosure 60 under influence of the fan 66.
Under the influence of pu~incJ, as descrihed above, ~owder is caused ~o drop ~rom the outsicle of the bacJ ~ilters 118, 119, 120, 121, 122, 123 which powder then ralls onto the i.nwardly slanting walls 104, 108, contacting khe knurled roll 112. The po~der which is deposited in this manner in the intermediate zone i.s then dropPed onto the web 31 as the powder is brushed from the roll 112 by t,he hrusl~
An alternative method o dro~ping excess powder onto the web 31 is to have an endless conveyor belt in the position of the sloping floor 108 carr.y the excess powc~er to a hrush in the position of roll 112, ~hich brushes the powder of~ the belt.
By virtue of the above description it can be seen that only filtered air is removed from the enclosure 60 and thak the escape of powder is virtually completely, eliminated. Furthermoxa, because o~ the automatic cleaning of the ba~ filters such as the hag filter 118 ~11 r30wc~er that enters the enclosure 60 is eventually depositsd on the web 31. ~n additional advantage is kl~a~ ~okh sides of the w~b 31 ar~ contacted with powder.
Call~ g the up~er sic~e o~ tIl~ weh 31 .its ~irst si(~e it can be seen tllat the ~irst side of the ~eb 31 is cont~cted wi~h po~er ~s the web 31 is supportecl by the conveyor 7~. IIow~ver, as the web 31 is supported on the second conve~-.)r 7~ it i5 the second side o~ the web 31 that is directly exposed to the po~er issuin~ ~rom the wAnd In l~his manne~ both sicles o:E ~h~ w~3b 31 a.re ;Lntima l:e1y cont:aatecl wi.th powder ~ ~here:~or~, wh~?n th~
pow-'ler~ l~r~atQcl web 3 9 i.~; axc~s~-1a~?ped ont:o th~ conveyo.r ~S ~5 as shown in Ficlur~s 1 ~nd ~ b~ m~ans of t:he cross-layincl meallan L.~;m 13; ~ach ~i,clo o:~ ~h~ we}- is con-~:ac~ d ~^til~h ~ si.~l~ o~ h~ ha1: has p.re:vious.ly b~en coated with powder. When the powder contains a thermo-plastic or thermo-s~tting adhesive this coating of both sides of the web is exceedingly important since it ensures good bonding between layers of the web and reduces the tendency of the finished batt to delaminate.
A wide variety of fibers can be employed in the present invention including those of cotton r poly~
est~r, acrylic r nylon, wool r polypropylene, modacrylic, acetate, and mixtures thereof.
10The apparatus and process of th~ present invention can be employed with a wide variety of powders.
Examples of classes of powders includ~ among others thermo-plastic resins, thermo-setting resins, and inorganic materials. Specific exampl~s of thermo- ;
plastic resins include among others polyethylene, polyvinyl chloride, and copolym~rs of vinyl chloride and vinylidine chloride. Sp~cific examples of thermo~
setting resins include among others phenol-formaldehyde resins, urea-formaldehyde resins, and other thermo-setting resins well known to impart wash and wearcharacteristics to fabrics.
~ wide variety of inorganic materials can be employed to impart flame resistance, ylow resistance, and other properties to the final batt. Specific examples of inorganic materials include amoncJ others boric acid, diammonium phosphat~ and monoammonium phospha-te The batts producecl in accordance with the pre~ent invention find utility as padding in mattresses, and in upholstered furni~ure of all kinds such as cha:irs and 30fas.
The invention may be under~tood by reE~r~.nc~
to the ollow:lncl non-limitinc3 ex~mples. The~e examples are desicJned to ~aah those skill~d in th~ art how to practiae the invqntlon ~nd r~present the be~t mode con-templated Eor prackicincJ the inventinn~ Unle.~s c)-th~.rwise specieied, ~11 parts ancl percentaCJe3 ax~ by weicJh~.
i~
~IL5g3:L 7 JJ~X_m~ 1 ~ r~o~?der which is a copolymer of vin~l chloride anfl vinyliclene chloride available ~rom th~ DOW Chemical Compan~ idlana, r~chigan~ uncier the designation Saran Resin 506 is added ~o a ~ihrous web in the manner described above ~ith respect to the drawings. This co~olymer has a weight ratio of vinyl chloride to vinyl-idene chlorlde of 10:90, a chlorine content of 71~; a plasticizer content of 1~; a minimum particle 9ize 0
POWDER I~ITH A FIBROUS ~:B
Disclosure It is known to apply dry powders to webs during the formation of bat~s ~or various purposes. For example, dry powdered boric acid is fre~uently applied to garnett webs of cotton which are subsequently cross laid or cross- `~
lapped on a mo~ing conveyor ~o fo~m a batt, said batt having a certain degree of fire resistance resulting rom ~he application of the boric acid powder and its mixture with the cotton in the web ana the battO
Other well-known processe~ involve ~he applica-tion to the web o~ either ~hermo-se~ing resins or thermo-lS plastic resins in dry powdered ~orm, generally but notnecessarily ollowed by cross-lapping the web to form a batt which is subsequen~ly heated. In the case o~ thermo-s~tting resins the makerial stiffens the fibers in the batt structure as the thermo-setting resin goes through the process of melting and hardening. A limited amount o~ bonding between fibers may occur with these resins.
Thermo-plastic resins, on the other hand, generally flow ; ~o a greater extent on the fiber surfaces as the ba~t is heated, so ~hat the melted resin ~o~ms more sites for 2S inter-fiber bonding. The s~rength anc~ unctional utilit~
of the bonds thus oxmed dep~nd on the characteris~ics o~ the the~mo-plastic resin, including its flow proper~ies, its melting point, its tackiness or s~ickiness in molten ~orm, and the tougl1ness o~ the resin bond when it has been coolea agai.n to a temperature below i~s sof~ening point.
~ arlous methods o~ appl~ing dr~ powdered materi-al ~ ko ~ibrou~ webs h~v~ b~n di~closed in paten~s and pu~licationsl and s~veral o~ these me~h~d~ have ~ouncl wicl~pr~ad commeraial appliaa~ion. Fo.r ~xc~lplo, one o 35 tilG mosk wid~l~ us~d ~k~pe~ o~ powder appl.tca~ors is the s~rewqr, whl~h is ~ss~ntiall~ a hopper cJener~ havln~
.
S~317 a more~or-less V-shaped cross section. At ~he bottom of khe "V" various means are used to meter out the required quantity of powder which thereafter falls by gravity onto the surface of the f"ibrous web wh~ch passes continuously beneath the strewer. Knurled rolls~ doctor-blades, com-~inations o~ br~shes and rolls, series of brushes, per-forated rolls and belts, and other d~vices are used to release the desired ~uantity of powdered material ~rom the strewer hopper. A~ the same time ~arious devices may be needed to keep the powdered material uniformly suspended and distributed within the strewer hopper itself. Several types of paddles are sometimes emplo~ed, ~ibrators of various types are used, and in some cases the powdered material is even fluidized ~o ensure ade~ua~e flow through the metering device.
Strewers have many disadvantages. The strewer width must conform closely to the width o~ the fiber web in order to avoid either a loss of powder if the strewex is ~7ider than the web, or to avoi~ areas of web which are untreated if the strewer is not as wide as the web.
Metering a precise amount of powdered material is dif- -ficult, as the many ~arieties of strewer will attest.
Among the major problems is the fact that the powder which is dropped by gravit~ tend~ to remain on the top of the web, khus leaving fibers which are untreated. With cer-tain ~unctional powders this leaves part o the ha~, non-~unctional or unpro~ec~ed, or in the case of bonding re,sins, ~i~es rise to the formation o~ a batt which has characteristia laminar quali~ies because layers which are bonded together b~ the resin carried on one side of the w~b alternate with layers between which there is little or no resin. ~nother di~advankage o~ strewers is that l~he~ ~nd ~o produce axa~ssive amoun~s o~ powder du~ in kll~ air wh~c~ is di~:~.icul~ ~o con~ol, A :Eux~h~r d.i~-3S ~iaul~ with ~r~w~rs is ~ha~ ~h~ powder must be me~r~clin~o the 5trewer to maintain some reasonabl~r aonstarlt ~ 93~ 7 supply of makerial while at the same time it must be metered out to ensure application of the proper amount o material onto ~he fibrous web. A double metering system has been employed in an e~fort to overcome this disad-S vantage, however such a;system has ~he additional problemof coordinating the rates of the two systems.
Qther methods of applying dry powdered ma~erials to fibrous webs produced by carding or garnettlng overcome some of the disadvantages of the strewer but introduce other problems w~ich ma~ include non-uniformity o appli-cation, low efficiency o~ powder usage, excess dust in the air, and incomplete coverage of the fiber web assembly.
Because o~ their shortcomings few, if an~, of these methods have found widespread comme~cial application~
Examples of prior art processes are describecl for example in Fleissner U.S. Patent 3,765,971 and in Buck et al. U.S. Pakent 3,993,518, hereinafter referred ko simply as "Buck".
Accordingly, i~ i~ an object of the present invention to provide an improved dr~ process for contacting a powder with a web and or producing a batt which processes are substantially free o~ ths disadvantages o~
the prior art.
~nother objeck is to provide a method for the in~nate uniform lmpregnation of the 1bers with the powclered material.
Still another object is to provide a method wherein the tendency of the la~ers o the web ~o form dis~inct laminations in the finished batt is eliminated, or minimized.
Ye~ another object is ko provida an improved rn~hod wherei.~ an even ~reatment oP powder over khe en~:irc wid~h o:E t~ ihrous w~b .i~ achieved.
S~ill a~o~h~r obj~ is ~O provide an ~mprovecl 3S m'e~hod whe.reln virtually ~ompleto aontai~nenk ~nd control ,~ o~ powd~ dust i.s achieved.
. . .
5~3317 Yet another objec~: is to provide an improv~d method whexein essentially lOOn~ efEiciency in the use of khe powdex is attained.
Still ano~her object i5 to provide an improved ap~aratus lor intimately contacting a powcler with a web~
Yet another object is to provide an improved ap~aratus for practicing the process of the present invention.
~ dditional objects and advanta~es of the present invention will be apparent to those skilled in the art by reference to the followin~ detailed description and to th~ drawings which are briefly described below.
Figure 1 is an elevation view o~ an apparatus suitable for practicing the process of the present inv~n-tion.
Fi~ure 2 is a plan view of the apparatus ofFigure 1.
Figure 3 is a sectional view taken along Line 3-3 of Figure 2.
Figure 4 is an enlarged sectional view taken along Line 4-4 of Figure 2.
Figure 5 is a secti~nal view t~ken along Line 5-5 of FicJure 4 which is identical to ~ine 5-5 of Figure 1.
Fi~ure 6 is a schematic, exploded view of the powder distribution wand which i5 also shown in Fi~ure 5~
Figure 7 shows a powder distribution means that is an alternative ~o the wand of Fiyure ~
Figure 8 shows a hag filter and is a sectional ~iew taken along Line 8-8 of Figure 4.
Figure 9 shows the ~oraminous belt with a web thereon and i~ an enlar~ed sectional view taken alon~
Line 9-3 o~ Figure ~.
'r~l~ abov~ ancl okhex objc-3a~.s axe accompll~hecl ~c~orclin~ ~o the pr~n~ inv~n~iorl b~ providin~ a proc~s~
~or lntima~el~ contac~irlg a ~ow~er with a movincJ ~ibxou5 web comprisi.ng the st~ps o~:
~ . c~ownwa~dly p~sing a mixtur~ Oe po~rder ancl air t~lrough the movirlg ~ihrou~ WC3~;
- - - -5~13~7 II. reversing the direction o movement o~ the fibrous web; and then III. passing a mixture of p~der and air through the moving ihrous w~b in a direction opposite to that 5 of Step I.
According to another aspect of the present inven-tion there is provided an apparatus for intimately con-tactin~ a movin~ ibrous web with a powder wherein the apparatus comprises~
A. a substantially air-tight ~nclosure;
B. means for maintaining subatmospheric pressure within the enclosure;
C. means for passing a fibrous moving web into the enclosure;
L5 D. means within th~ enclosure ~or passi.ng a first mixtur~ o powder and air through the moving ~ibrous web;
E. means ~or reversing the direction of mover,~ent o~ the fibrous web;
F. means or passing a second mixture o~
powder and air through the moving fibrous web in a direction opposit~ to the direction o~ the first mi~ture; and G~ means or passing the fibrous web ~rom the ~nclosure~
Th~ apparatus of the pre~ent invention includes an enclosure in which the fibrous web is ~reated with powder. Generally this enclosllre is located immediatel~
after the dofer of a garnett or cardiny machine, and ahead of the cross-lapping apparatus which depos~ts khe web on the :Eloor apron. O~ course the apparatus ma~ be usecl e~uall~ well to treat webs which are not cross-~.a~Qcl hu~ ~Ihi.ch cc>n~inue ~rom the a~paratus :in a ~andem clr~an~em~n~ he~ ~or ~ur-~r treal~ment, suGh as h~atin~
:in an oven, ox for paal~acJing ~n rolls or other ~orms~
l`he ~nclosure in which the web is treak~d prefer~bly has onl~ wo openings, on~ through which ~he weh enters, and a second .~rom whi.ch ik exi~ a~t~3x krcak-me.n t . Tha~a o~enill~Ts are g~nerally, althou~ nok neces-sarily, formed by pairs of rolls betwe~n which kha ~ibrous 3~
web passes. The po~Jc~ered material to be applied to the weh enters the enclosure in one or moxe enclosed pipes.
Air ls e~-hausted from the enclosure by a fan operating through filters as ~escribed below.
No convevor ~or the web enters the enclosure, or e~its from it. The elimination of such conveyors reduces the openings into the enclosure, and also eliminates the possibilit~ that ~he conveyors themselves will carr~ powdered material out o the enclosure. In the ap~aratus of the present invenkion the fibrous web simply leaves a conveyor ar.d itself enters the appli~ator enclosure. In the same way, it leaves an internal conveyor at a point within the enclosuxe before exitin~
the enclosure bètween a pair of rolls. There are, of course conveyors for the fibrous web ~hich are within the applicator enclosure, but these conveyors remain en~
tirely inside the enclosure so that they neithex require entrance or exit ports, nor can they carry any powdered material out o the enclosure.
The entire enclosure is maintained under nega-tive pressure. Thus there is a tendency for air to enter the applicator enclosure along with the fibrous web at the entrance port and even or some air to enter the en-closure around or bet~reen the rolls at the exit port.
The maintenance of a signi~icant ne~ative pressure within the applicator enclosure prevents the dust or powdered material from escapincJ into khe area outside the enclo-sure. Generall~ the negative pressure within the enclosure is mainkained b~ employing an exhaust fan which draws air throu~h a series of bag filters which axe contained ~Jithin the enclosure. Alternative arrarlcJernents such as cyclone~, or c~clon~s accompaniecl b~ eill~ers, may al~o be use~ but ar~ le~9 pre eerred~
Wikhin t~ ~nclosure ~he ~ibrous web~ suppor~ecl 3~ in par~ ~y conveyors, ma]ces a~ leask one chancJe in cli~
rec~ion. 'I;~his ~rmi~ botll sides o~ khe web to b~ -~r~ate~
~1~9317 with the powdered material which is injected into an air stream which moves in a single downward direction. The drawings discussed below illustra~e an enclosure in which the web makes kwo changes o direction, but an S enclosure having a single change in direction may ac-complish the purposes described above. It will be noted that the powdered material passes through the web at least twice, from opposite sides of the web, but that the powdered material itself moves in a single downward direction.
Excess powder in the air is captured on the bag ilters or similar devices and redeposited on the web. In order that this redeposition be made in a uniform manner, generally the bag filter is placed within a separate chamber inside the main applicator enclosure so that when shaking or reverse~pulse air puffing removes the accu~ulated powder from the bags it falls within the separate chamber from which it is dispensed uniformly and evenly across the width of the web passing beneath by a suitable series o~ rolls and brushes, or combina-tions thereof, or alternatively by a suitable vibratoxy ~eeder. The powdered material itsel~ is introduced into the applicator enclosure suspended in a rapidl~ moving airstream contained in a suit~ble con~eyor pipe. The precise amount of powdered material needed for applica-tion to the fibrous web is metered into thi~ airstream by a sui~able means, such as a screw feeder or vibratory ~eeder and generally enters the airstream itself through a venturi device. After the powdered material has entered the applicator enclosure through the air pipe in which it is suspended, it is distributed across the width o~ the fiber web and literally blown through the web by a sui.~ahle di~ributing de~ice xe~erred to herein as a w~nd or dis~rlbu~or, se~eral examples o~ whiah are 35 ;illuskr~t~d ix~ l~he drawing~ h~r~:in. A~ leasl~ one wand or powde dlstributor i~ used. When a single wand or powder 5g317 distributor is used, part o~ the powder being a~plied is blown com~letely through the web, thexeafter im~in~ing the weh a second time on the opposite face a~ter khe web has made a turn within the applicator enclosure. Gen-erallyr however, it is;preferable to emplo~ a second wandor powder distributox to assure that sufficient powdered material is applied to the second side and then it in turn also has an o~portunity to penetrate the entire web structure.
The excess powder which has passed through the eb from both sides is collected and redeposited once again on the fiber web to ensure its cvmplete and ~f-~icienk use in the process. In the configuration in which the web makes at least two changes o~ di.rection much of the powdered material simply falls onto the top of the fiber web as it makes its final pass within the appli-cator enclosure, after which it is carrie~ ~rom the en-closure with the exiting web. At least a part of this powdered material, after passing through the web at least twice, is picked up and circula~ed back to the bag filter through plenums on either side of the enclosure which collect that excess p~wder ~rom the bottom of the appli-cator enclosure. This recaptured powder is subse~uently redeposited into the top surface o~ the web ~rom the ba~
~iltar apparatus as described above.
~ 11 the conveyor belts which support and aarxy tlle web on its passage through the applicator enclosure are ~raminous and are of an open mesh type, permitting free ~assa~e of air and powder through both the web and the conve~or belt where this is necessar~ and desirable.
'rhU5 it i5 ~ossible to maintain a continuous ~low o~ air in on~ downward direation thxou~h the web and the hqlts, ~a~ dir~c~ion h~in~ ~oinciden~al wi~h the direction .in which th~ pow~er is in~ectqd into th~ wehs ~rom the wand~ or powcler distributors.
~55~3 ~7 Various rneans, including the use of compressed air fed through flexible hoses may be used to keep the powclered material sufficiently suspended in the bottom o the applicator e~closure so that it can be picked up i.n the return airstream:~hich 10ws thxough the side plenums or ducts to ~he bag filters a~ the top of the enclosure.
~ eferring now to the drawin~s and in particular to ~igures 1 and 2, there is shown an apparatus 10 useful for ~racticing the process o the present inven-tion. The apparatus 10 com~rises an opener or a garnett 11, an apparatus 12 for applying powder, a cross-la~ing mechanism 13 and, as shown in Figure 2, an oven 14, and cooler 15. The garnett 11 comprises an inlet 15 chute 18 adapted to feed bulk fibers to the rotating drum .s 19 of the garnett 11. The garnett 11 is also provided with a pluxality of tooth rolls 21, 22, 23, 24, 25 which, together with the teeth not shown on the drum 19, -take bul]c fibers 20 and convert them ko a web 31 which adheres to the drum 19. The web 31 adherin~ to the drum 19 is transferred to the drum 28 where it is removed by a comb 29. The thin, planar web 31 that is now only between 1 and 100 fibers thick and is barely sel~-supporting entexs the apparatus 12 in a hori~ontally di.sposed posi~ion, where it is contacted with a ~owder as described moxe completely below.
The powder-treated web 39 then goes to the conve~or 41 and thence to the conve~or ~2. In a manner well known in axt, the lower end of the conve~or ~2 is attached to a traveller 43 which moves baclc and forth on a track 44. The conveyor 4~ is positioned above and a~ ri.~hk an~les to a conveyor ~5. The aonveyors ~2 and ~5 are ~cljusted such that ~he 3peed o~ ~he conve~or ~2 .~s ~everal ~ime~ ~a~r ~han ~he ~pe~3d of kh~ conve~or ~5. ~ v:lrkue o~ ~hi.s arrangemen~, khe web 39 is aross-la~e.d hack ancl ~orth on the conveyor ~S thus formin~
l~ ~L5~3 ~7 --10-- , an unheat-treated batt 47. The unheat-treated batt 47 passes on~o a foraminous belt 50 (see Fi~ure 3) which passes into the oven 14~ As shown in Figure 3, the oven 1~ is provided with ~eaking ~eans 52 which can be ther-mostat:icall~ controlled by a thermostat 53. The oven14 is also provided with air circulating means not shown that causes the air to circulate in the direction shown by the arrows 55 and 56. Ba~fles not shown are provided at either side of the batt to insure that the air cir-culates through, rather than around, the batt. The~ebaffles are adjustable, to accomodate batts of different widths.
After leaving the oven, the batt 47 then enters an enclvsed transition chamber not shown betw~en the oven 14 and cooler 15, where it pas~es from the belt 50 of the oven and entexs between an upper ~or~`nous belt 49 and a lower foraminous belt not shown which compresses the batt 47~ The upper belt 49 can be raised or lowered by means not shown, to control the thickness of the final batt. While held and compressed between the two belts, the batt 47 enters a cooler 15~ In the cooler 15, cool air is moved by an air circulatin~ means not shvwn through the batt 47 and the two foraminous belts. In this manner, the resin is ~rozen and the batt 47 assumes the ~hickness it had while compre~ed between the two belts.
The resultant product is the ~inal heat-treated ba~t.
Refexring now to Figures 4 and 5, there is shown in sectional view the apparatus 12 for applying powder to the web 31. The apparatus 12 has an air-tight enclosure 60. The air-tight ~nclosure 60 divides ~he appara~us 12 into a low~r ~one 62, an intermediate æone 6 3, ancl an upper zone G ~ . :Cn ~he lower zon~3 G ~, I:hq we~ is con~ac~ wikh powd~r. ~n ~he in~ar~
35 medi~e xona 63, l:lle exces~ powder is collecked and :Eed baclc onta th~ web 31. In kha upper zone 6 ~ air is remove~l by a ~an fi~ drivan b~ a motor 67.
~lS~3~7 The lower zone 62 i~ provided with an entrance comprising an opening 70 to facilitate access of the web 31, and two rotating rolls 72, 73 adjacent to the open-in~ 70 which are provided with means (not shown) to cause them to rotat~ in the direction of the arrows as shown. Within the lowe~ zone 6~ is an endless conveyor 74 which moves around rollers 76, 77 each of which rotate around their respective axes in the direction o the arrows shown thereon. Balow the conveyor 74 is anoth~r endless conveyor 78 which moves around rollers 80, 81 in the direction of the arrows7shown. In the preferred embodiment depicted in Figure 4 the lower zone 62 is also pr~vided with a third endless conveyor 82 adapted to circula~e around rollers 83, 84. The lower zone 62 is provided with a powder distrihution wand 8~ positioned above the conveyor 74 and with a second pc~wder distribution wand 86 ' positioned above the con-veyor 78. The lower zone 6~ is provided with an exit opening 88 to permit egress o the web 39. Adjacent to and parallel to the opening 88 are two rolls 90, 91 rotating in the airection o~ the arrows as sh~wn. The bottom of the lower zone 62 is provided with inwardly sloping walls 92, 93 terminating in a central collectin~
well 9~. Within the well 94 is a stirrer 96 having Elexible outlet hose 98 which is adapted to receive air under pressure from a pipe 100 connected to a compressed air source not shown. Air leaving the stirrex 96 ~rom the hose 98 causes the stirrer 96 to rotate about the vertical portion of the pipe lO0.
The intermediate zone 63 is provided with a :Eirs~ lower wall 104 which slopes downwardly and inwardl~
~rom the ~orwarl wall 106 o~ th~ aix~ h~ enclo~ure G0.
h~ lntermediak~ xone ~3 is ~lso provid~d with a ~eaoncl :l~wcr wall lO~ wh~ch ~lopes downwardl~ and inwardly ~rom 3.'j tlle rea.r w~ll llO o~ the enclosure 60. rrh~ extren~e lowe~
encl o~ the wall 1~ and the extreme l~wer encl o~ th~ wall 3~7 108 define a slot over the first conveyor 7q in which rotates a roll 112. The surface of the roll 112 is grooved or knurled in order to permit powder to adhere ~hereto. Below the roll 112 is a cylindrical brush 114 ada~ted to brush the,~urface of the rvll 112 and remove powder therefrom. The roll 112 substantially fills the slot formed by the lower extremities of the walls lO~, 108.
The intermediate zone 63 is provided with an upper wall 116. Depending from the upper wall 116 are a series of bag filters 118, ll9, 120, 121~ 122, 123. The bag ilter 118 is provided with a compressed air pipe 124 terminating in a nozzle 126. The pipe 124 is provided with a valve 128 controlled by a timer 130. Each of the bag filters ll9, 120, 121, 122, 123 and other bag filters not numbered are also provided with sources o~ high pressure air similar to the pipe 124.
Referring now to Figure 5 it can be seen that the enclosure 60 is provided with an external plenum 13 in the form o~ a rectangular pipe 133 having a lower opening 134 in fluid communica~io~ with the bottom of the lower zone 62 and having an upper opening 136 in fluid communication with the intermediate zone 63.
The enclosure 60 is also provided with a second plenum 138 having a lower opening 140 and an upper opening 142 the purpose and ~unction oE which are more completel~
dascribed below.
Referring now to Figure 6 there is shown a powder m~tering and distribution apparatus 144 compris.ing a hopper 146 adapted ~o hold powder 148. The bottom o ~he hopper 146 is in communication wi~h a screw conveyor L50 adap~ed to be turned by a variable spaed motox 152.
'rha ~pe~d o~ ~he mo~or 15~ d~exmine~ ~hQ amoun~ o~ powd~r 154 leavin~ ~he ~nd o~ ~ha ~crew conveyor 150. I'he powd~r 3~ 15~ d~ops inko ~ second hopp~r 15~ wh:ich i~ up~traam o a vent~lr~ 15~ suppli~d with a ~ource o~ high pre.~ure air ~not shown) ~ia plp~ 160 ~exminating in nozxle 16~. The -- - ~
~L55D317 venturi 158 ensures thAt the powder 154 will be admixed with ~he air when the powder-air mixture 161 leaves the venturi 158 via the pipe 164. The pipe 164 i5 in fluid communication with t~e pipe 166 which in turn is in ~luid communication with the wand 86. As shown in Figure 6 the wand 86 has been ro~ated 90 to more clearly show its structure. However, the area transvers~ to flow of the powder-air mixture 161 continually decreases such that the amount o~ the air-powder mixture 161 leaving the firs t opening 168 is thei same as th~ amount o aix-powder mixture 161 leaving the last opening 170~ All structure shown in Figure 6 is in the priox art.
~eferring now to ~igure 7 there is shown an alternative pswder distribution apparatus 17~. The apparatus 172 comprises a pipe 17~ adapted to be in ~luid communication wi~h the pipe 164 of Figure 6. Attaahed to khe pipe 174 is a deflection plate 1~. The defleation plate 176 comprises a ~irst portion 17B substantially parallel to the direction of flow as shown by the arrow 181~ The plate 176 comprises a second portion 180 joined to the first portion 178 by an intermediate curved portion 182. Positioned on the second portion 180 is a V-shaped deflector 184 the vertex 186 of which i5 placed directly in line with the powder flow as shown by the arrow 181.
I~eferring now to Figure 3 r there is shown the bag filter 118 in an enlarged view. The bag ~ilter 118 comprises a first metal plate 188 provided with a plurality o~ holes such as the holes 190, 192~ The bag ~ilter 118 i5 provided with a second plate not shown parallel to the ~irst plate 188. A cloth bag 19~ is placed over and completel~ 3urxoun~ the ~lat~ 183 an~
~he pa~allel ~la~ no~ ~hown. ~c~ powdor aolleat3 on kh~ c~u1:~3id~ o~ ~h~ bag 1~4 and w:ill be hqld th~r~ b~ th~
di;~e~r~nce .in pres~ure on ~he ou~sid~ o~ the ba~ 19~ ~
compared to the pressure on ~he in~ide o~ th~ ba~ 19~.
IIowever kh.is pc>wder can be caus~d to be disloclgt~d lE
~ g31~
the air pressure on the inside o~ the bag 1~4 is tempo-rarily increased by a puff of high pressure air from the nozzle 126.
Referring ~ow to Figure 9 there is shown the roller 80 with its endless conv~yor 78 supporting the web 31.
The operation of the apparatus 12 is best under-.: stood by reerence to Figure 4. In operation the web 31 enters the air-tight enclosure 60 through the opening 70 and through the nip of the rolls 72, 73. Th0 web 31 then falls onto the conveyor 74 and, as it moves laterally, passes underneath the ~irst discharge o~
powder caused by the action o~ the brush 11~ against the roll 112. The web 31 now carried by the conveyor 74 passes underneath the wand 86 th~reby rece~ving a second dose of powder~ The web 31 is then ~urned downward and around on an axis perpendicular to the direction o move-ment of the web 31, until the web 31 is moving in a revexsed direction and passes onto the foraminous belt of conveyor 78~
Some of ~he powder issuing rom the wand 86 is retained on the web 31. A portion of the powder-air mixture passes through the web 31, ~hrough the upper portion o~ the conveyor 74 through the lower portion of the conveyor 74 an~ again contacts ~he web 31 while the web 31 is supported by the conve~or 78. As the web 31 suppor~ed by the conve~or 78 passes underneath the wand 86' a third dose of powder is given to the web 31~
Some of the powder issuing from the wand 86' is retained on the web 31~ However, a portion o~ the p~wder-air mix~ure passe~ through ~he web 31 thxough the upper portion ~ tha conveyor 78 and through ~he lowor por~ion o~ ~ha con~or 78 and ~hen a~aln con~acts the 3S web 31 wh:Lle ~he web 31 is supported on the upper portion o~ the conveyor 82~ The wab 31, whiah is now termed a powcler-~reatea we~ 3~, is aaxrled by ~he upp~r por~.ion 3~7 of the conveyor 82 and then passes through the nip of rolls 90, 91 and exits from the enclosure 60 throu~h the opening 88~
Air is removed from the enclosure 60 by the ~an 66. The fan 66 draw,s air from the upper ~one 64 of the enclosure 60, ~rom the inside o the bag ilters 118, 119 r 120, 121, lZ2 and 1~3~ and upward through the plenums 132 and 138. The fan 66 creates subatmospheric pressure within the enclosure 60 in general and in particular within the lower zone 62, the in~ermediate zone 63, and the upper æone 64 as shown by the li~uid level in the manometer 196. Since the enclosure 60 is under a subatmospheric pressure external air tends to leak into the enclosure 60 whereas dust and powder-laden air are prevented ~rom escaping. Air is supplied to the enclosure 60 as part of the air-powder mixture supplied by the wands 86, 86' and as part of the compressed air issuing from the hose g8 of the stirrer 96. Furthermore, air leaks in~o the enclosure 60 through the openings 70, 88.
However, a size of an 66 and dri~ing motor 67 are selected in order to remove all of the air that enters the enclosure 60 from any source whatsoever while still maintaining a subatmospheric pressure within the enclosure 60 as s~own by the manometer 196. The pre~erred subatmospheric pressure is between one half and five inches of water.
Another important aspect o~ the present inven-~ion is ~he internal ~low o~ powder ~nd o~ air. Powder is supplied to the web 31 by means o~ the wands 86, ~6'.
However the powder which drops to the bot~om of ~he lower zone 62 o~ ~he enclosure 60 encounters the inwardl~
slanting walls ~2, 93 and drops into the well ~4 where the powder is again entrained in air by means o~ the s~irrer 96. r~he ~an 66 drr~ws air ~rom ~he opening 136 as shown ;in ~igure 5 ~rom the plenum 132 and also ~rom 35 ~l~he W~ll 94 ~hrou~h ~he openlng 13~. Thl~ ensu~ tlla~
~lie ~en~ral :elow oE ai.r and powder i9 downward :Ln tho lc)wer zone 62 and is upward in the plenums 132, 13~ .
rrhe powdar-aix mis~ture is drawn to the ba~s 194 -16~ 93~7 (s~ Fi~3ure 8) ~.~hereupon the powcler s~ops on the outside of the ba~ and the air travels throug}- the ba~ 19~
through the upper zone 6~ of th~ enclosure 60 and from the enclosure 60 under influence of the fan 66.
Under the influence of pu~incJ, as descrihed above, ~owder is caused ~o drop ~rom the outsicle of the bacJ ~ilters 118, 119, 120, 121, 122, 123 which powder then ralls onto the i.nwardly slanting walls 104, 108, contacting khe knurled roll 112. The po~der which is deposited in this manner in the intermediate zone i.s then dropPed onto the web 31 as the powder is brushed from the roll 112 by t,he hrusl~
An alternative method o dro~ping excess powder onto the web 31 is to have an endless conveyor belt in the position of the sloping floor 108 carr.y the excess powc~er to a hrush in the position of roll 112, ~hich brushes the powder of~ the belt.
By virtue of the above description it can be seen that only filtered air is removed from the enclosure 60 and thak the escape of powder is virtually completely, eliminated. Furthermoxa, because o~ the automatic cleaning of the ba~ filters such as the hag filter 118 ~11 r30wc~er that enters the enclosure 60 is eventually depositsd on the web 31. ~n additional advantage is kl~a~ ~okh sides of the w~b 31 ar~ contacted with powder.
Call~ g the up~er sic~e o~ tIl~ weh 31 .its ~irst si(~e it can be seen tllat the ~irst side of the ~eb 31 is cont~cted wi~h po~er ~s the web 31 is supportecl by the conveyor 7~. IIow~ver, as the web 31 is supported on the second conve~-.)r 7~ it i5 the second side o~ the web 31 that is directly exposed to the po~er issuin~ ~rom the wAnd In l~his manne~ both sicles o:E ~h~ w~3b 31 a.re ;Lntima l:e1y cont:aatecl wi.th powder ~ ~here:~or~, wh~?n th~
pow-'ler~ l~r~atQcl web 3 9 i.~; axc~s~-1a~?ped ont:o th~ conveyo.r ~S ~5 as shown in Ficlur~s 1 ~nd ~ b~ m~ans of t:he cross-layincl meallan L.~;m 13; ~ach ~i,clo o:~ ~h~ we}- is con-~:ac~ d ~^til~h ~ si.~l~ o~ h~ ha1: has p.re:vious.ly b~en coated with powder. When the powder contains a thermo-plastic or thermo-s~tting adhesive this coating of both sides of the web is exceedingly important since it ensures good bonding between layers of the web and reduces the tendency of the finished batt to delaminate.
A wide variety of fibers can be employed in the present invention including those of cotton r poly~
est~r, acrylic r nylon, wool r polypropylene, modacrylic, acetate, and mixtures thereof.
10The apparatus and process of th~ present invention can be employed with a wide variety of powders.
Examples of classes of powders includ~ among others thermo-plastic resins, thermo-setting resins, and inorganic materials. Specific exampl~s of thermo- ;
plastic resins include among others polyethylene, polyvinyl chloride, and copolym~rs of vinyl chloride and vinylidine chloride. Sp~cific examples of thermo~
setting resins include among others phenol-formaldehyde resins, urea-formaldehyde resins, and other thermo-setting resins well known to impart wash and wearcharacteristics to fabrics.
~ wide variety of inorganic materials can be employed to impart flame resistance, ylow resistance, and other properties to the final batt. Specific examples of inorganic materials include amoncJ others boric acid, diammonium phosphat~ and monoammonium phospha-te The batts producecl in accordance with the pre~ent invention find utility as padding in mattresses, and in upholstered furni~ure of all kinds such as cha:irs and 30fas.
The invention may be under~tood by reE~r~.nc~
to the ollow:lncl non-limitinc3 ex~mples. The~e examples are desicJned to ~aah those skill~d in th~ art how to practiae the invqntlon ~nd r~present the be~t mode con-templated Eor prackicincJ the inventinn~ Unle.~s c)-th~.rwise specieied, ~11 parts ancl percentaCJe3 ax~ by weicJh~.
i~
~IL5g3:L 7 JJ~X_m~ 1 ~ r~o~?der which is a copolymer of vin~l chloride anfl vinyliclene chloride available ~rom th~ DOW Chemical Compan~ idlana, r~chigan~ uncier the designation Saran Resin 506 is added ~o a ~ihrous web in the manner described above ~ith respect to the drawings. This co~olymer has a weight ratio of vinyl chloride to vinyl-idene chlorlde of 10:90, a chlorine content of 71~; a plasticizer content of 1~; a minimum particle 9ize 0
2 microns, a maximum particle size o~ 50 microns, ancl an average size of 11 microns. The powder is added at a rate such that it increases the weight oP the web by 15~. The oven temperature is 425F.
Exam~le 2 _ ._... _ The procedwre of Example 1 is repeated except that ~he po~7der is r~laced by a powd~r tha~ par~s ]~ weicJht of the copolymer of Exa~ple 1 and 1 part hy wei~ht of monoammonium phosphate.
Althou~h the invention has been described in considerable detail with reference to certain preferred embofliments tllereof it will be understood that modifica-tions and variations can be made without departing from the s pirit o~ the invention as given above ~nd without departin~ from the scope of the appended claims.
Exam~le 2 _ ._... _ The procedwre of Example 1 is repeated except that ~he po~7der is r~laced by a powd~r tha~ par~s ]~ weicJht of the copolymer of Exa~ple 1 and 1 part hy wei~ht of monoammonium phosphate.
Althou~h the invention has been described in considerable detail with reference to certain preferred embofliments tllereof it will be understood that modifica-tions and variations can be made without departing from the s pirit o~ the invention as given above ~nd without departin~ from the scope of the appended claims.
Claims (4)
1. A process for intimately contacting a moving fibrous web with a powder comprising the steps of:
I. passing a mixture of powder and air through the moving fibrous web;
II. reversing the direction of movement of the fibrous web; and then II. passing a mixture of powder and air through the moving fibrous web in a direction opposite to that of Step I.
2. A process for intimately contacting a moving fibrous web with a thermally activatable adhesive powder comprising the steps of:
I. downwardly passing a mixture of powder and air through the fibrous web while the fibrous web is moving laterally;
II. reversing the direction of lateral movement of the fibrous web to a direction opposite to the direction of lateral movement in Step I thereby passing the moving web directly underneath that portion of the moving web moving in accordance with Step I; and then III. downwardly passing a mixture of powder and air through the moving fibrous web in a direction opposite to that employed in Step I.
3. The process of Claim 2 wherein steps I
through III are performed in a substantially air-tight enclosure.
4. The process of Claim 3 further comprising the step of maintaining the enclosure at subatmospheric pressure.
5. The process of Claim 3 further comprising the step of moving the web into the enclosure between two rollers.
6. The process of Claim 3 further comprising the step of moving the web out of the enclosure between two rollers.
7. The process of Claim 2 further comprising the step of collecting excess powder which has fallen through the moving fibrous web in a collecting well below the web.
8. The process of Claim 7 further comprising the step of conveying the excess powder Prom the collecting well to a zone of the enclosure located above the moving web.
9. The process of Claim 8 further comprising the step of dropping the excess powder from the zone above the web down onto the web.
10. The process of Claim 8 wherein the excess powder is conveyed by an upward moving airstream.
11. The process of Claim 9 wherein the excess powder is dropped uniformly across the width of the web.
12. A dry process for producing a batt comprising the steps of:
I forming a horizontally disposed, thin, planar web of fibers, said web being from 1 to 100 fibers thick;
II moving the fibrous web laterally on a foraminous belt;
III downwardly passing a mixture of particles of a copolymer of vinyl chloride and vinylidine chloride and air through the fibrous web while the fibrous web is moving laterally;
A. wherein the weight ratio of vinyl chloride to vinylidene chloride in the copolymer is 5:95 to 25:75, B. wherein the weight ratio of the copolymer to the fiber is 10:90 to 20:80, C. wherein the copolymer particles have a size range of 2 microns to 100 microns, D. ; wherein the particles fall on the web and through the web and the belt under the influence of gravity, IV turning the web downward and around on an axis perpendicular to the direction of the web's original lateral movement until the direction of lateral movement of the fibrous web is reversed to a direction opposite the direction of lateral movement in Steps II and III, thereby establishing a reversed portion of the web;
V passing the reversed portion of the web onto a second foraminous belt lying directly underneath that portion of the web moving in accordance with Step II wherein the particles falling through the moving web and the belt in accordance with Step III fall on the reversed portion of web and excess particles fall through the reversed portion of the web and the second belt;
VI downwardly passing a mixture of the particles and air through the reversed portion of the web in a direction opposite to that employed in Step III, wherein excess particles fall through the reversed portion of the web and the second belt;
VII collecting the excess particles in a collecting well under the belts:
VIII drawing air upward through two plenums from the collecting well to a zone above the web;
IX conveying the excess particles in the collecting well in the upward moving airstream in the plenums to the zone above the web;
X depositing the conveyed excess particles in the zone above the web;
XI dropping the excess particles from the zone above the web down onto the web;
XII forming the web into a batt by laying the web transversely back and forth on a moving belt such that the batt comprises a plurality of webs;
XIII heating the batt to a temperature of 400°
to 450° while the batt is being passed through an oven on a foraminous belt while hot air is forced through the belt and through the batt to melt the copolymer;
XIV cooling the batt to room temperature while the batt is being passed through a cooler between two parallel foraminous belts while cool air is forced through the belts and the batt to resolidify the copolymer.
13. An apparatus for intimately contacting a moving fibrous web with a powder comprising:
A. a substantially air-tight enclosure;
B. means for maintaining subatmospheric pressure within the enclosure;
C. means for passing a fibrous moving web into the enclosure;
D. means within the enclosure for passing a first mixture of powder and air through the moving fibrous web;
E. means for reversing the direction of movement of the fibrous web;
F. means for passing a second mixture of powder and air through the moving fibrous web in a direction opposite to the direction of the first mixture;
and G. means for passing the fibrous web from the enclosure.
14. The apparatus of Claim 13 wherein the means for maintaining subatmospheric pressure within the enclosure comprises a fan.
15. The apparatus of Claim 13 further comprising foraminous support means within the enclosure for supporting the web.
16. The apparatus of Claim 15 further comprising A. means for collecting excess powder which falls through the web and the foraminous support means, B. means for conveying the collected excess powder to a position above the web, C. means for dropping the excess powder located above the web onto the web.
17. The apparatus of Claim 13 wherein the means for passing the fibrous web into the enclosure comprises two rolls tangent to each other and rotating in opposite directions, between which the web passes.
18. The apparatus of Claim 13 wherein the means for passing the fibrous web out the enclosure comprises two rolls tangent to each other and rotating in opposite directions, between which the web passes.
19. An apparatus for producing a batt, the apparatus comprising:
A. a garnett comprising:
1. an inlet chute, 2. a rotating drum having teeth on its surface, the drum being rotated at the end of the inlet chute, and being fed bulk fibers by the inlet chute, 3. a plurality of tooth rolls tangent to the rotating drum, which convert the bulk fibers into a web, 4. a second rotating drum tangent to the first drum rotating in a direction opposite that of the first drum, and picking up the web from the first drum, 5. a comb which removes the web from the second drum;
B. a substantially air tight enclosure having lower, intermediate, and upper zones, 1. the lower zone comprising:
a. an entrance located near the comb through which the web moves after being removed from the second drum, b. a first endless conveyor having a foraminous belt for moving the web laterally away from the entrance slit, c. a second endless conveyor having a foraminous belt, the second conveyor lying underneath the first conveyor and moving in a direction opposite therefrom, the second conveyor being positioned to receive the web as it leaves the first conveyor, d. a third endless conveyor having a foraminous belt lying underneath the second conveyor, the third conveyor being positioned to receive the web as it leaves the second conveyor, e. an exit lying near the end of the third conveyor, f. a first powder distribution wand located above the first conveyor, the powder distribution wand comprising: a horizontal wand having a plurality of openings along its length on its lower side, a powder source at an end of the wand, and a source of high pressure air blowing powder down the length of the wand, g . a second powder distribution wand identical to the first powder distribution wand, the, second powder distribution wand being located above the second conveyor, and below the first conveyor, h. a collecting well at the bottom of the lower zone into which excess powder falling through the web and the foraminous belts of the three conveyors will settle, i. a horizontal flexible hose at the bottom of the collecting well, the hose being rotatable about a verticle axis, 2. the intermediate zone comprising:
; a. a downwardly slanting lower wall, the lower end of the wall being over the first conveyor in the lower zone, b. a means for dropping powder from the lower end of the wa11 onto the web, c. a plurality of bag filters extending into the intermediate portion, the bag filters being pervious to air but impervious to the powder;
3. The upper zone being in fluid communication with the bag filters, and containing a plurality of pipes, each pipe leading into one of the bag filters;
C. Two plenums lying outside of the enclosure and alongside the lower zone, the plenums being in fluid communication with the collecting well and leading from the col1ecting well to the intermediate zone;
D. A fan located at the top of the enclosure, the fan being in fluid communication with the upper zone and drawing air upward, whereby the fan draws air through the bag filters and plenums, and whereby excess powder in the collecting well is drawn upward in an airstream and deposited on the outside of the bag E. A compressed air source connected to the plurality of pipes in the upper zone, whereby air may be blown into the bag filters to release the powder collected on them, the powder then falling to the lower wall of the intermediate zone;
F. A second compressed air source connected to the hose of the collecting well whereby excess powder in the collecting well is forced out of the collecting well and into the conduits;
G. Conveying means for conveying the web away from the exit of the enclosure;
H. A cross-laying means comprising:
1. a traveler at -the end of the conveying means, 2. a track upon which the traveler moves back and forth, 3. a fourth endless conveyor under the track moving at a right angle to the motion of the traveler and moving more slowly than the conveying means, whereby the web is cross-layed on the fourth conveyor and formed into a batt, I. An oven comprising:
1. a foraminous belt which conveys the web from the cross-laying mechanism into and through the oven, 2. heating means, 3. air circulating means whereby heated air is made to travel through the batt and the foraminous belt;
J. A cooler comprising:
1. a lower foraminous belt located to receive the batt leaving the oven,
2. an upper foraminous belt directly above and parallel to the lower belt and in contact with the batt on the lower belt,
3. means to raise and lower the upper belt whereby the thickness of the batt can be controlled,
4. a second air circulating means to draw cool air through the batt and the upper and lower foraminous belts.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US7467779A | 1979-09-12 | 1979-09-12 | |
| US074,677 | 1979-09-12 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1159317A true CA1159317A (en) | 1983-12-27 |
Family
ID=22120979
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000358724A Expired CA1159317A (en) | 1979-09-12 | 1980-08-21 | Process and apparatus for contacting a powder with a fibrous web |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP0025543A1 (en) |
| AU (1) | AU6206380A (en) |
| CA (1) | CA1159317A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4457793A (en) * | 1982-01-15 | 1984-07-03 | Fiberlok, Inc. | Method for producing a fiberous batt |
| NL8502947A (en) * | 1985-07-16 | 1987-02-16 | Flexline Services Ltd | METHOD AND APPARATUS FOR IMPREGNATING THREADS OF DIFFERENT FILAMENTS, RIBBONS OR THE LIKE WHICH, IF POSSIBLE, IN A FABRIC OR KNITTLE, E.D. BE PROCESSED. |
| SE0001929L (en) * | 2000-05-23 | 2001-12-21 | Christian Hoegfors | Process for producing a thermosetting resin-containing fibrous web, such a fibrous web, and a reinforced thermosetting composite comprising the fibrous web |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4053674A (en) * | 1975-09-12 | 1977-10-11 | Fiberlok, Inc. | Glow-resistant batt and process for producing such |
| DE2603884A1 (en) * | 1976-02-02 | 1977-08-04 | Jun Alfred Thies | Yarn tow dyeing appts. - in which tow is fed along endless helical path has two vertically spaced endless conveyors with perforated belts providing tow support |
-
1980
- 1980-08-21 CA CA000358724A patent/CA1159317A/en not_active Expired
- 1980-09-02 EP EP80105197A patent/EP0025543A1/en not_active Withdrawn
- 1980-09-05 AU AU62063/80A patent/AU6206380A/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| EP0025543A1 (en) | 1981-03-25 |
| AU6206380A (en) | 1981-03-19 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry | ||
| MKEX | Expiry |
Effective date: 20001227 |