AU9419298A - Hot melt adhesive applicator with metering gear-driven head - Google Patents

Description

I

AUSTRALIA

Patents Act COIMPLETE SPECIFICATION

(ORIGINAL)

Class Int. Class Application Number: Lodged: Complete Specification Lodged: Accepted: Published: Priority Related Art: Name of Applicant: Illinois Tool Works Inc.

Actual Inventor(s): Edward W. Bolyard. Jr.

L eonard E. Riggan, Jr Address for Service: PHILLIPS ORNIONDE FITZPATRICK Patent and Trade Mark Attorneys 367 Collins Street Melbourne 300)0 AUSTRALIA Invention Title: HOT MELT ADHESIVE APPLICATOR WVITH MIETERING GEAR-DRIVEN HEAD Our Ref 562295 POF Code: 1431/1431 The follovving statement is a full description of this invention, including the best method of performing it known to applicant(s): a. *1 -IP AUST

RALIA

Iln A) 99 8

I\

~s12~- I e r..

2 HOT MELT ADHESIVE APPLICATOR WITH METERING GEAR-DRIVEN HEAD This is a divisional application divided out of Australian application no. 24701/97 the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION The invention relates generally to a system for dispensing fluids onto a .io substrate, and more particularly to a system having a manifold coupled to an array of S adhesive dispensing nozzles for precisely dispensing hot melt adhesives supplied from a reservoir to the manifold by a metering gear pump.

The precise dispensing of hot melt adhesives and other fluids onto substrates is required in many applications. The manufacture of a variety of bodily fluid absorbing hygienic articles including disposable diapers and incontinence pads, sanitary napkins, patient underlays, and surgical dressings, for example, often requires bonding one or more layers of material, or substrates. These layers of material include, more specifically, a fluid impermeable. highly flexible thin film such as poiypropylene or '"i polyethylene onto which is adhered a highly absorbent pad often formed of a cellulose or plastic material covered by a non-woven fleece-like material. The fluid impermeable S thin film, however, is extremely temperature sensitive, and hot melt adhesives have a :tendency to deform the film and in some cases melt through the film. Materials bonded in other applications are similarly temperature sensitive.

It is known to dispense hot melt adhesive onto a substrate from nozzles that form thin fibers or stands of adhesive, which are nearly invisible to the naked eye and incapable of melting or distorting the substrate. In many applications, a plurality of adhesive dispensing nozzles are arranged generally in an elongated array directed toward the substrate, which is usually moved transversely relative to the nozzles. The hot melt adhesive is very often supplied to the nozzles from a reservoir by a gear pump including several fluid outlets, which simultaneously supplies precisely metered amounts of adhesive to several corresponding fluid dispensing nozzles. U.S. Patent 3 No. 4,983,109 to Miller et al., for example, discusses several gear pumps interconnected by a common manifold assembly, including a pump manifold and a distribution manifold, to a plurality of nozzles wherein each gear pump simultaneously supplies precise amounts of adhesive to several corresponding nozzles. Each nozzle is specially configured for coupling with a corresponding adhesive supply conduit alone or in combination with a corresponding air supply conduit. A blocking plate configuration permits blocking alternatively the nozzle to prevent adhesive dispensing wherein the blocking plate recirculates adhesive back to the adhesive reservoir. or back to the gear pump.

The inventors of the present invention recognize that controlling the temperature of compressed air combined with the hot adhesive in the:nozzle is an effective means for controlling the adhesive dispensed by the nozzle. U.S. Patent No.

4,983,109 to Miller et al., however, is not capable of independently controlling air S temperature since compressed air is supplied through the common manifold assembly, which is maintained at a temperature required for adequately supplying and properly dispensing adhesive. The inventors of the present invention also recognize that it is desirable to recirculate adhesive as a means for dynamic pressure regulation. which may be required in the event adhesive flow through the one or more nozzles becomes o: obstructed, which occasionally occurs over time. Prior ar ht melt adhesive applicators generally regulate pressure by limiting current to the motor that drives the gear pump, or by a clutch assembly that slips to limit load on the motor resulting from excessive fluid pressure. In U.S. Patent No. 4,983,109 to Miller et al., adhesive is recirculated only when the nozzle is replaced by the specially configured blocking plate, which includes an internal passage interconnecting the adhesive supply conduit and the recirculation conduit. The blocking plate is however not intended to dispense adhesive or to 7 gulat ssure in the event that an operational nozzle becomes obstructed.

In view of the discussion above, there exists a demonstrated need for an advancement in the art of fluid dispensing systems. It is therefore an object of the invention to provide a novel system for dispensing fluids which substantially overcomes or at least alleviates problems in the prior art.

1 It would be desirable to provide a novel system for dispensing hot melt adhesives through a plurality of nozzles coupled to a manifold wherein hot melt adhesive is supplied to the nozzles. from a reservoir, by a common metering gear pump coupled to the manifold. vwhich forms a metering gear-driven head. It would also be desirable to provide a novel system usable for dispensing hot melt adhesives wherein the system includes adhesive dispensing nozzles for modifying dispensed adhesive with compressed air at a temperature controllable independently from an adhesive temperature.

It would be useful to provide a novel system usable for dispensing hot melt adhesives including a plurality of adhesive dispensing nozzles coupled to a main manifold wherein fluid pressure is regulatable by recirculating adhesive toward the reservoir or toward the metering gear pump. Furthermore, it would be useful to S. provide a novel system usable for supplying hot melt adhesives from a reservoir by a metering gear pump, dispensing hot melt adhesives through a plurality of adhesive dispensing nozzies coupled to a main manifold, and regulating fluid pressure by S recirculating adhesive toward the reservoir through a recirculation manifold interchangeably coupled to the main manifold.

It would be advantageous to provide a novel system usable for dispensing hot melt adhesives, supplied from a reservoir by a metering gear pump, wherein the.

system includes a metering gear-driven head having a main manifold with a well for I receiving the metering gear pump, and a common heating member for heating the S main manifold and the metering gear pump. It would also be advantageous to provide a novel system usable for dispensing hot melt adhesives wherein the system includes a plurality of adjacently mounted main manifolds coupled to a plurality of fluid dispensing nozzles separated by substantially equal spacing therebetween and arranged along the plurality of adjacently mounted main imanifolds. In addition, it would be useful to provide a novel system usable for dispensing hot melt adhesives wherein the system includes a plurality of adjacently mounted main manifolds each having a second fluid supply conduit coupleable to a second fluid supply conduit of an adjacent main manifold.

-3

Z

a

K

I;

.F~I -uo SUMMARY OF THE INVENTION According to the present invention there is provided a system usable for dispensing fluids including hot meit adhesives. supplied from a reservoir by a fluid metering device, onto a substrate. the system including: a plurality of fluid dispensing nozzles: a main manifold having a plurality of fluid supply conduits, each fluid supply conduit coupleable between the fluid metering device and a corresponding fluid dispensing nozzle. the main manifold having a fluid recirculation conduit disposed between each fluid supply conduit and a corresponding recirculation outlet port ;o disposed on a recirculation module interface: and a recirculation module for recirculating fluid from the main manifold to the reservoir, the recirculation module having a plurality of fluid inlet ports disposed on a mounting surface of the recirculation module interchangeably mountable on the recirculation module interface of the main manifold wherein fluid inlet ports of the recirculation module are coupleable with corresponding recirculation outlet ports of the main manifold.

SIn a preferred embodiment of this invention the main manifold includes a plurality of pressure monitoring ports in the recirculation module interface for S independently monitoring pressure in the corresponding fluid supply conduit, the recirculation module including a plurality df pressure monitoring ports coupleable with a corresponding pressure monitoring port of the main manifold when the recirculation module is interchangeably mounted on the recirculation module interface of the main manifold.

The above and other features and advantages of the present invention will become more fully apparent upon consideration of the joilowing Detailed Description of the Invention with reference to the accompanying drawings, which may be disproportionate for ease of understanding, wherein like structure and steps are referenced by corresponding numerals'and indicators.

BRIEF DESCRIPTION OF THE DRAWINGS FIG I is a fluid flow schematic for a fluid dispensing system according to an exemplary embodiment.

rn r oo l 6 ~1~w 4- FIG. 2 is a fluid flow schematic for a fluid dispensing system accoring.to a first.

alternative embodiment.

FIG. 3 is a fluid flow schematic for a fluid dispensing system according to a, second alternative-embodiment FIG. 4 is a fluid flow schematic for a fluid dispensing system accordirg to a third alternative embodiment.

FIG. 5 is a partial sectiona! view. taken along lines I I in FIG. 6. of a fluid.

dispensing system according to an exemplary embodiment of the present invention.

FIG. 6 is a partia: top view of a hot melt adhesive dispensing system of the type ;o shown in FIG. 5'configured according to an exemplary embodiment of this invention.

FIG. 7a is a partial sectional view of-a recirculation manifold according to anexemplary embodiment.

FIG. 7b is a partial sectional vie;" of a recirtulation manifold according to an alternative embodiment., FIG. 8 is a partial sectional.. 'iew of a pressure relief valve according to an exemplary embodinient.

FIG. 9a is a partial top view of a hot melt .dhesive dispensing system of the type shown in FIG. 5 configured according to another embodiment.

FIG. 9b is a partial side view taken along lines ii II of the FIG. 9a.

DETAILED DESCRIPTION OF THE INVENTION The present invention is suitable generally for dispensing fluids onto a substrate in a variety of applications, including applications where precise dispensing of fluid onto the substrate is required, and the invention is suitable particularly for precisely dispensing hot melt adhesives of the type used for bonding layered materials in the manufacture of hygienic articles.

According to the invention as illustrated in the exemplary fluid flow schematics of FIGS. 1 through 4. the fluid dispensing system 10 comprises generally a plurality of nozzles 20 interconnectable to a fluid reservoir, or tank. by a plurality of fluid supply conduits 30 and one or more fluid metering devices, or pumps, which independently supply fluid from the tank to each of the plurality of nozzles 20 through a corresponding fluid supply conduit 30. In another configuration, the system 10 includes i '1 i

_A

.j- _RmULP

I

.i 1 o ~1 l-+r+ uirr r rr~

I

r a plurality of recirculation conduits 40 each interconnectable between a corresponding fluid supply conduit 30 and the tank by a plurality of one-way valves each disposed along a corresponding recirculation conduit 40. The one-way valves conditionally recirculate fluid froni the corresponding fluid supply conduit 30 toward the tank.

wherein fluid isrecirculatable either back to the tank or back to the pump. The one-way a'ives are generally configured to recirculate fluid when pressure in the fluid supply conduit 30 exceeds a predetermined fluid pressure threshold. The one-way vaaies. moreover, independently regulate pressure between the pump or pumps and -the.corresponding nozzies 20 without affecting the pressure inthe remaining nozzles.

n the exemplary fluid fiow schematics of FIGS. 1. 2 an4i the one-way valve is -a normally cldsed check valve 50. The system 10 also inclu js at least one normally ciosed one-way pressure relief valve 60 disposed between he plurality or one-way 'dhecck valves 50 and the tank. The check vaives 50 are independently operated one-way valves, and are opened to recirculate fluid toward the tank when pressure in th: corresponding fluid supply conduit 30 exceeds a first threshold pressure. The pressure relief valve 60 is opened to recirculate fluid toward the tank when the pressure between the check valves 50 and the pressure relief valve 60 exceeds a S second threshold pressure. which is greater than the first threshold pressure. The S check valves 50 independently regulate pressure between the pump or pumps and the 20 corresponding nozzles 20 without affecting the pressure in the remaining nozzles. In one application, the first threshold pressure of the check valves 50 is several psi greater than the desired fluid pressure in the fluid supply conduit 30. and the second threshold pressure of the pressure relief valve 60 is between approximately 2 and 3 times the desired fluid pressure in the fluid supply conduit 30. In the exemplary fluid flow schematics FIGS. i1 2 and 4. a manually operated pressure discharge valve, not shown, may also be disposed betwieen the plurality of check valves 50 and the pressure relief valve 60 for relievind fluid pressures below the second pressure threshold, which is useful for resetting the system. In another configuration, a plurality of air supply conduits 70 each are interconnectable between aii air supply not shown and a corresponding nozzle 20 wherein the air supply conduits 70 supply compressed ^-rx l^-r air to the nozzle usable for modifying a fluid pattern dispensed therefrom as further discussed below. The exemplary fluid flov,'schematic of FIG. includes a normally closed diverter valve 80 disposed between the ,furality of one-way check valves 50 and the tank in parallel to the normally closed pressure relief valve 60. The diverter valve 80 relieves fluid pressure between the plurality ofeck valves 50 and the pressure relief valve to reduce fluid pressure in the fluid soia conduits 30 when the pump is energized and the plurality of nozzles 20 are closed. The diverter valve 80 reduces the tendency for fluid to surge through the nozzles 20 when the nozzles are first opened. The t1 diverter valve 80 is a particularly desirable feature for applications where the nozzles 20 are opened and closed intermittently. In operation, the normally closed diverter valve 80 is opened when the nozzles 20 are closed, and the diverter valve is closed when the nozzles are opened. The diverter valve 80 also eliminates any requirement for the manual pressure discharge valve discussed above.

In the exemplary fluid flow schematic of FIG. 3. the plurality of one-way valves are a plurality of normally closed pressure relief valves 60. which are opened to recirculate fluid toward the tank when pressure in the corresponding fluid supply S conduit 30 exceeds a threshold fluid pressure. The pressure relief valves independently regulate pressure between the pump or pumps and the corresponding nozzles 20 without affecting the pressure in the remaining nozzles. In one embodiment, the threshold pressure is between approximately 2 and 3 times a desired S fluid pressure in the fluid supply conduit 30 as discussed above. In an alternative configuration, a plurality of air supply conduits 70 each are interconnectable between an air supply not shown and corresponding nozzles 20 wherein the air supply conduits 70 supply compressed -air to the nozzles for modifying a fluid pattern dispensed therefrom as further discussed below.

The exemplary fluid..flow schematics of FIGS. 1 and 4 include a pressure monitoring gauge 90 and pressure monitoring port 92 connectable between the plurality of check valves 50 and the pressure relief valve 60 for monitoring an average fluid pressure therebetween, which.results from pressure increases in any one or more of the plurality of fluid supply conduts 30. According to the alternative fluid flow j"' i sch-ernazics of FIGS 2 ru.zL; moioi" ziaces 9- ar ports 952 a r ee a ch c or, ner a 0! u c 1 odu nd,:dually e '30 ev.n a -'Acco-rdina c arr ME H~s- m c~a Xi are either replaced Cr~o' 'se~a~r onncxm t -ilc or Visual alarm -o -~~r~~CIIn fluid. ;;hich often Md;: c':rc.:r c .2 20n::20.I re CO JA! tc FIGS- I and 4. a sincle rcr' 7 Vrn iC to :na; orC:-Ssure 201 'l dri ro generally that onie or mor.e 30 zire cr u lr does not specificaPly dof7, sue.- -Cou 30 rejjj jr~~ Intle configurations of FIGS 2 3ux .z c cric-i '30 anc n-1- Z* 20 trcludes a corresponding transducer rt .4 jtn por w f py c-ui orC condluits 30 that are In some, app iurkos 's ~i !on eoaibocoea'mrfld supply condiuitS 30 andr r frm- :he c!oocke'd flu SU supCi.- confiults 0 tow,%ard the reservo:,' an.j.. .lr orC o-nrv'C nci tftiat fluid is recirculating from th- b';c'rec flui c' oord;ts 30. %lore specf!fiai~y ore or more nozzles 20 may be intentioriahyi -uned off or r-eplaced ,i-th a bio po Oi t that obstructs fluid flow from a ;!uic suaLv--' conidiu;t 30. Under these circiumstancc f! id from the biOoclhed fluid suopty condui.;ts 30 is gene rally recirculated to either the fluid pump or the flud reserva'r. Reicua inofu~d tshrouch the recirculation conduit hov.ever, precludes use or an alarm fo, k!-dicati,-o u-nrentionai fluid rewsrution.

which may occur as a result of amn. ob-structLed riozzt--- AccordinG to an alternative embodiment- recirculation condui: 2- couoied To either one or more closed nozzles o- fluid supply conduit biocklina plates. recirculates fluid from the corresponding fluid supply conduits 30 towa. rd the reservoir._ In the exemuiarv. enmboim.ent or FIG&. 5 and 6- the system '10 include5 a main manifold 100 havinc a t -r.tvo nuic supply condui 30 cu~ot li ~trn 3o device 300. which irdeciendenitiv tucies Pflu i om a fluid r-aservoir, oDr tanlk .,ner '.n the combination forms a metering gear-onsven head. The main manifoid 100 incliudes I I I~ a first end portion 102 with a plurality, of fluid outlet ports 32 each for coupling a corresponding fluid supply conduit 30 to a corresponding fluid dispensing nozzle In an alternative embodiment, the main manifold 100 includes a second end portion 104 with a plurality of fluid outlet ports 32 for coupling a corresponding fluid supply conduit 30 to a corresponding fluid dispensing nozzle 20, wherein the fluid metering device supplies fluid to either or both end portions 102 and 104 of the main manifold 100.

d In one embodiment. the fluid metering device 300 is a metering gear pump having a fluid inlet 320 coupled to the tank and. a plurality of independent fluid outlets io 330 each coupled to a fluid supply conduit 30 for providing precisely metered amounts of fluid to a corresponding nozzle 20. According to this embodiment, a single fluid metering device 300 independently and simultaneously supplies fluid to several fluid supply conduits 30 and nozzles 20. A pump suitable for this application is Model No.

HSJ-62260-7000-0. having a fluid inlet port and eight fluid outlet ports. available from Parker Hannifin Corporation. Zenith Pumps Division. Sanford. North Carolina.

The main manifold 100 alternatively includes a well 110 for receiving the fluid- S metering device 300. An adapter plate 120 with a plurality of conduits 122 may be alternatively disposed between the fluid metering device 300 and the main manifold 100 for appropriately routing and coupling the fluid outlet ports 320 of the fluid metering device 300 with the fluid supply conduits 30. A sealing member may be disposed between the adapter plate 120 and the main manifold 100. A pump supply S conduit 130 is disposed in the main manifold 100 for supplying fluid from the fluid reservoir, or tank. to the fluid metering device 300. In one embodiment. fluid is supplied from the tank to the-pump fluid supply conduit 130 through a fluid filter 140 mounted in the main manifold 100. The fluid filter 140 includes a fluid inlet port 142 for coupling with the tank. A heating member disposed in the main manifold 100 hea.s the fluid metering device 300 and the main manifold 100 thereby providing a relatively efficient means for heating the fluid. which eliminates the requirement of a separate heating element and insulation for the fluid metering device 300. In the embodiment of FIG. 6, the heating member includes a plurality of heater cores 150 disposed in a corresponding recess in the main manifold 100. In one embodiment, one or more

A

I

temperature sensors are disposed in the makr cr;-r:;'foci1,0 for io ortr data to a heatino member *temoneratur-;e c r In n ateriane eoo'met. s 'ocy cndu 16 na.~an tniet port 162 on an upper side of temain manvo-100 e-Lend be:n. ;een a fit! P ort ',61 -on a first side 106 oif itbe main manifgld 10C and a second coti 166 ona second sid e 108 of the main manifold. The sunpiv conduLit, 160 cou.ien punT~ SuPPY conduit 130. and the inlet Pori 162_ is ooupied to -the rarns -or suyinc Nut id [c the- fuid metering device 300, The ccons 1 5- and 166 are ocoebeto corr-spcndtnci oorts on one or more othier mai malnifocs.!:a~c- ietc tu Fo min manifold '100.

mountabie adjacently on the iirst side 10O6 and tLhe second 3ide 103 of the mainl manifold 100 to Form an array of main manifolds. 1n-14-FlG.- 6. a second side 108- of a second main maniloid 100 Show-n r. crt s m oun a ad0;acentIY t o the fi s t si de 0 6 of the main manifold 100 sc thte second flid- rrr..q '.160 of h second ma11n manifold 100' is coupled to- the second Put-d condui' c60 o the man anfoido 100to this arrangement. fluid ;s supplied io both main manifolds by cnurilnOI the fluid reservoir, or tank. to the fluid inlet '62 of the rnamn maniftold 100- An': of unused ports 162. 164 and 166 of the conduit '160 in the array of main manifolds may be plugq 60. In the exempir mbdmn all but one of the fluid iiet ports 162. and the first port 154 and second port 166 on, the outermost sides of array of main mnanifoids are plugged. The fluid suoplie fro t he second fluid conduit 160 may be fitered by filter 140 in each main manifold before flowino to the inlet port 320 of the fluid metering device 300- In the exemplary embodiment, each of the oluralitv of flui-d dispensing nozzles is part ofs a nozzle module 200 that is actuatable pn-eurnaticaill to -open a nd cIo s e Sthe nozzle 20 on command. The r. zze modules 200 aisro have the caa~iY to cmine, fluid fromn th e fl uid supplv conduit 30 withi combressed aii for precisely controllina an amount andJ cattern of fluid.dispernsed from the nozzle 20. The nozzle module 200' includes a flud 1; iterface 21 wi vth a fluid infet port 23J2 for coupiing ;vithia fluid supply conduit 30. arid air iniez por-ts 214 1 and 21.5 for acaictfinq the nozzle: module 3o 200. The nozzle mr-odule also inc-ludes an air interface 220 viith- an air por 222 for providing compressed air to tenozzle- 20. A nzl oueo~tcirvsial o rrarrnrrrr*nl rrr~ cr this purpose is the MR-1300'" Nozzle Module, available from ITW Dynatec, Hendersonville, Tennessee.

In the exemplary embodiment, the fluid interface 210 of the nozzle module 200 is mountable on either the first end portion 102 or the second end portion 104 of the main manifold 100 for coupling the fluid inlet port 232 with a corresponding fluid supply conduit 30. The main manifold 100 includes air supply conduits 170 corresponding to each fluid supply conduit 30 and coupleable to the air inlet ports 214 and 216 of each nozzle module 200. In an alternative embodiment, however, air for actuating the nozzle module 200 may be supplied to an outer side of the nozzle module 200, which 10 eliminates the requirement for the air supply conduits 170 in the main manifold 100.

In the exemplary embodiment, the fluid metering device 300 includes eight fluid outlets 330 capable of independently supplying fluid to eight corresponding nozzles through corresponding fluid supply conduits 30. The main manifold 100 of the exemplary embodiment may therefore be configured for dispensing fluid up to eight nozzles 20 at any one time by coupling nozzles 20 to corresponding fluid supply conduits 30 on either the first or second end portions 102 and 104 of the main manifold 100. A blocking member 500 is mountable over the unused fluid supply conduits 30, and in alternative embodiments the blocking member may block also the air supply conduits 170. The fluid in some blocked fluid supply conduits 30 is recirculated back toward the fluid reservoir, or tank, as further discussed below. Other embodiments may include additional fluid supply conduits 30 in the main manifold 100 and may employ a fluid metering device with more or less than eight fluid outlet ports.

FIG. 6 shows a plurality of nozzles 20 arrangeable along the first end portion S102 of the main manifold 100 wherein a spacing between adjacent nozzles 20 is substantially equal. The spacing between the nozzles 20 is based on a spacing between a central portion 230 of adjacent nozzles 20. In the exemplary embodiment,the fluid supply conduits 30 also have substantially equal spacing therebetween so that the spacing of the nozzle modules 200 is substantially equal. The spacing between the side portions 106 and 108 and the outermost fluid supply conduits however is approximately one-half the spacing between adjacent fluid supply conduits interior of the side portions 106 and 108. According to this configuration, the feS.. r- m u iZN. LI-I.4rrsn;-

.L

a r"

I

j a, 13 central portion 230 of the nozzles 20 coupled to the sidemost fluid supply conduits is spaced similarly from the corresponding side portion 106 and 108 so that the central oortions 230 of the sidemost nozzles 20 of adjacently mounted main manifolds 100 have the same spacing as the other nozzles.

5 FIG. 6 also shows the fluid supply conduits 30 on the second end portion 104 of the main manifold 100 offset relative to the fluid supply conduits 30 on the first end portion 102 of the main manifold 100. According to this configuration, nozzles mounted on the second end portion 104 of the main manifold 100 are offset relative to nozzles 20 on the first end portion 102 of the main manifold 100. The offset spacing of lo the central portions 230 of the nozzles 20 disposed on opposing sides 102 and 104 of the main manifold 100 provides an interleaved fluid dispensing pattern. This offset arrangement of nozzles 20 on opposing ends of the main manifold 100 effectively forms an array of nozzles 20 with reduced spacing between the central portions 230 of adjacent nozzles compared to the nozzle spacing available by disposing nozzles on only one side of the main manifold 100. The reduced nozzle spacing is useful for some fluid dispensing applications.

An air preheater module 400 with a preheater interface 410 is mountable on the air interface 220 of a plurality of adjacently mounted nozzle modules 200, and may include a recessed portion 412 to reduce heat transfer from the air preheater module 400 to the nozzle modules 200. The air preheater module 400 includes a compressed air inlet port 420 for directing compressed air through an arrangement of parallel conduits 430 disposed over heating members 440, whereinthe parallel conduits 430 have relatively increased surface area, which improves heat transfer to the air. The heated air is directed into a common plenum 450, and through a plurality of air supply conduits 460 each having an outlet port 462 coupleable to a corresponding air inlet port 222 of a corresponding nozzle module 200. An adjustable throttling valve 470 is disposed in each air supply conduit 460 for controlling heated air flow therethrough.

The location of the air preheater 400 on the outer side of the nozzle module-200, apart from the main manifold 100. permits controlling the temperature of the compressed air independent from the temperature of the main manifold 100, which provides improved control of fluid dispensed from the nozzle 14 FIGS. 5 and 6 further illustrate an alternative configuration wherein the system includes a plurality of recirculation conduits 40 each interconnectable between a Icorresponding fluid supply conduit 30 and the fluid reservoir, or tank, by a plurality of one-way valves V each disposed along a corresponding recirculation conduit 40. The 5 main manifold 100 includes a second interface 180 on which is mountable a recirculation manifold 600 having a recirculation interface 610. The second interface a9 180 of the main manifold 100 includes a plurality of recirculation outlet ports 182 for coupling the plurality of recirculation conduits 40 to a plurality of recirculation inlet ports 612 on the recirculation interface 610 of the recirculation manifold 600 as further discussed below.

In one embodiment, the plurality of one-way valves V are a plurality of one-way check valves 50 each disposed along a corresponding recirculation conduit 40 in the main manifold for recirculating fluid toward the recirculation manifold 600 when the S fluid pressure in a corresponding fluid supply conduit 30 is at a first pressure threshold as discussed above. A check valve suitable for this application is Model No. 2206 available from Kepner Products, Villa Park, Illinois. In the exemplary embodiment of FIG. 7a, the recirculation manifold includes a fluid discharge port 620 coupled to the fluid reservoir, and a normally closed pressure relief valve 60 disposed in a corresponding recess in the recirculation manifold 600. The pressure relief valve opens to recirculate fluid from the recirculation conduits 40 to the discharge port 620 and toward the tank when the fluid pressure between the check valves 50 and the pressure relief valve 60 is at a second pressure threshold as discussed above. A pressure relief valve suitable for this application is Model No. CP 208-3 available from Compact Controls, Hillsboio, Oregon. In an alternative embodiment, the check valves 50 are disposed in the recirculation manifold 600. The recirculation manifold 600 also includes a pressure monitoring port 92 for receiving a pressure monitoring gauge which monitors an average pressure between the check valves 50 and the pressure relief valve 60 as discussed above. The recirculation manifold 600 is interchangeably mountable on the main manifold 100 with recirculation manifolds having other configurations. A pressure transducer connectable to an indicator or alarm may f C~T~--~~C~MPWPY~ rr.Pp~-li~.~L

B

I

K

alternatively be coupled to the pressure port 92 for indicating that fluid is being recirculated from one or more fluid supply conduits 30 as discussed above.

In the embodiment of FIG. 7b, a recirculation manifold 600 is configured similarly to the embodiment of FIG. 7a. and includes additionally a normally closed diverter valve 80 disposed in a corresponding recess in the recirculation manifold 600.

The diverter valve 80 is disposed between the plurality of one-way check valves and the tank in parallel to the normally closed pressure relief valve 60, and is coupled to the fluid discharge port 620 of the recirculation manifold 600 by a fluid outlet conduit 82. The diverter valve 80 facilitates relieving fluid pressure in the fluid supply conduits 1o 30 when the pump is energized and when the plurality of nozzles 20 are closed to reduce the tendency for fluid to surge through the nozzles 20 when the nozzles are first opened as discussed above. In operation, the normally closed diverter valve 80 is opened when the nozzle modules 200 are closed, and the diverter valve is closed when the nozzle modules are opened. A diverter valve suitable for this application is Model No. CP 508-2 available from Compact Controls, Hillsboro, Oregon.

In another embodiment, the plurality of one-way valves V are individual S pressure relief valves disposed in the main manifold 100, or disposed alternatively in a S recirculation manifold 600. FIG. 8 shows an pressure relief valve 700 of the type S disposable in the main manifold 100 having two matable body members 710 and 720 20 and a central bore 730 which houses a ball 740, or other similarly seatable member, biased toward a seat 750 by a coil spring 760 wherein the threshold pressure is determined by the spring constant. The pressure relief valves 700 may be used in combination with the recirculation manifold 600 of FIG. 7a by replacing the pressure relief valve 60 with a plug, which is not shown.

In the embodiment of FIG. 5. the main manifold 100 -includes, alternatively, a plurality of pressure monitoring ports 94 each coupled directly to a corresponding fluid supply conduit 30 for independently monitoring fluid pressure in the fluid supply conduit 30 with a corresponding pressure gauge 90. In the exemplary embodiments of FIGS. 5 and 6, the pressure monitoring ports 94 of the main manifold 100 are coupled to an array of. corresponding ports 92 in the recirculation manifold 600 where corresponding pressure gauges 90 are coupled to thepbrts 92. The pressure gauges t :i y

I-I

may alternatively be disposed in the main manifold 100. The recirculation manifolds of FIGS. 7a and 7b may also alternatively be configured with individual pressure monitoring ports for coupling with the pressure monitoring ports 94 of the main manifold 100. Absent corresponding ports 92 in the recirculation manifold, the ports 94 in the main manifold 100 are blocked and are unused. A pressure transducer connectable to an indicator or alarm may alternatively be coupled to each pressure port 92 in the recirculation manifold, or directly with the ports 94 in the main manifold 100 in configurations where the ports 94 are not coupled with the recirculation manifold 100, for indicating that fluid is recirculating from a corresponding fluid supply a conduit 30 as discussed above.

FIGS. 9a and 9b show a hot melt adhesive dispensing system of the type shown generally in FIG. 5 including a nozzle adapter plate 800 interconnecting the main manifold 100 and a plurality of nozzles 20: The nozzle adapter plate 800 includes a fluid interface 810 connectable to the first end 102 of the main manifold 100 and a nozzle interface 820 connectable to one or more nozzles 20. The nozzle adapter plate 800 includes a plurality of fluid supply conduits 830 interconnecting a corresponding fluid supply conduit 30 of the main manifold 100 and a corresponding 7 nozzle 20 mountable on the nozzle adapter plate interlace 820. In another configuration, the nozzle adapter plate 800 includes an air interface 850 with air supply ports for interconnecting the nozzles 20 and an air preheater module 400, which supplies compressed air for modifying fluid flow through the nozzles 20 as discussed S above.

According to another aspect of the invention, the nozzle adapter plate 800i ,q includes a recirculation conduit 840 for recirculating fluid from one or more fluid supply 25 conduits 30 toward the reservoir.. In one configuration, the recirculation conduit 840 is coupled to a recirculation conduit 42 in the main manifold 100 for recirculating fluid from the unused fluid supply conduit 830to the fluid supply conduit 130 in the main manifold 100. Generally, each fluid supply conduit 830 is selectably connectable to the recirculation conduit 840 by a valve or removable plug for recirculating fluid in the event that a corresponding nozzle is closed or a nozzle is replaced by a blocking member 500 as discussed above. According-to this configuration, fluid from any 11 1 I 2 17 blocked fluid supply conduit 830 is recirculated through the recirculation conduit 840 tovard the reservoir by opening the valve or removing the plug to couple the fluid supply conduit 830 to the recirculation conduit 840. According to another configuration, the recirculation conduit 840 is coupled only to one or more unused or blocked off fluid supply conduits 832 and 833, which is desired for some fluid dispensing applications.

While the foregoing writie'iescription of the invention enables anyone skilled in the art to make and use whatis: at present considered to be the best mode of the invention, it will be appre iated nd understood by those skilled in the art the existence "o of variations, combinatins.n oifications and equivalents within the spirit and scope of the specifi -exemplar i mbodiments disclosed herein. The present invention therefore is to e limitedIot by the specific exemplary embodiments disclosed herein but by all embodirnents',ihin the scope of the appended claims.

e e C

Claims (2)

1. A system usable for dispensing fluids including hot melt adhesives, supplied from a reservoir by a fluid metering device, onto a substrate, the system including: a plurality of fluid dispensing nozzles; a main manifold having a plura!ity of fluid supply conduits, each fluid supply conduit coupleable between the fluid metering device and a corresponding fluid dispensing nozzle, the main manifold having a fluid recirculation conduit disposed between each fluid supply conduit and .a corresponding recirculation outlet port disposed on a recirculation module interface; and a recirculation module for recirculating fluid from the main manifold to the reservoir, the recirculation module having a plurality of fluid inlet ports disposed on a mounting surface of the recirculation module interchangeably mountable on the recirculation module interface of the main manifold wherein fluid inlet ports of the recirculation module are coupleable with corresponding recirculation outlet ports of the main manifold. C.

2. A system as claimed in Claim 1 wherein the main manifold includes a plurality of pressure monitoring ports in the recirculation module interface for independently monitoring pressure in the corresponding fluid supply conduit, the recirculation module including a plurality of pressure monitoring ports coupleable with a corresponding pressure monitoring port of the main manifold when the recirculation module is interchangeably mounted on the recirculation module interface of the main manifold. DATED: 27 November, 1997 PHILLIPS ORMONDE FITZPATRICK Attorneys for: ILLINOIS TOOL WORKS INC.