GB2394256A - Dispenser for anaerobic curing compositions - Google Patents

Abstract

A dispenser for anaerobic compositions has a casing (2) adapted to withstand internal pressure with an internal flexible container (3) having walls permeable to air or oxygen which gas is filled under pressure into the casing (2) to surround the container (3). A dispensing valve (5) is connected to the flexible container (3) and is selectively operable to release the composition. In order to allow dispensing even when the container (3) is becoming exhausted, an elongate channel-defining rod (4) extends across an interior of the flexible container (3) from adjacent the valve (5) to a remote end. The channel-defining rod (4) comprises solid wall elements extending generally radially outwardly from its longitudinal axis and twisting to define at least one helical channel extending generally longitudinally of the rod (4) and connected along substantially its entire extent directly to an interior of the flexible container (3).

Description

DISPENSER FOR ANAEROBIC CUR1N(; COMPOSITl()NFi The present invention

relates to a container for the storage and dispensing: of curable compositions that cure in the absence of oxygen. More particularly but not exclusively, it relates to a dispenser for such compositions from which an improved proportion of its contents may be dispensed.

Anaerobic curing: compositions are those which remain as liquids in the presence of oxygen, but which E,olymerise to solids or gels in the absence of oxygen. Such compositions also polymerise in the presence of metal. even a solid metal surface. They are therefore widely used ha engineering instead ot' expensive or elaborate mechanical fixings or eomponents especially where metal components are to be fixed and/or sealed together. Common applications include threadloeking, nuts. retaining sealing and casketing.

I'o prevent premature polymerization and ensure long shelf lives such anaerobic adhesives and sealants are generally stored in plastics containers with a substantial free air volume above the liquid composition. I lovever. these products are generally higilly viscous liquids

! or even pastes. Thus a conventional manually-squcezabie plastics bottle or the like' having a restricted nozzle for accurate application. is not particularly convenient as a dispenser for such compositions. It is also very difficult to squeeze out as high a proportion of the contents of'suel1 containers as one might wish, and the anaerobic compositions are generally t:ar too viscous to flow out unaided.

While these compositions are highly effective when used correctly. they are also expensive to produce compared to most other forms of adhesive or sealant. It is hence a disincentive to using such products, if' there is a significant wastage that cannot be dispensed from the container. The recovery or disposal of undispensed product may also constitute an environmental, health and/or sat'ety problem.

Alternative forms of' container/disperser have been considered which are adapted to deliver a high proportion of a liquid contained therein. driven by pressurised gas (frequently, but strictly incorrectly. known as aerosols). conventional pressurized dispenser of this type has metal vvalls and would lead to polymerization of' its contents. A plastics equivalent would not he able to retain a gas pressure sui't'icient to deliver viscous anaerobic compositions. In any case' the composition should he delivered as a liquid not as a spray or a foam so direct composition/gas contact is undesirable.

It is known to dispense a liquid material from an aerosol'' container comprising: a flexible.

collapsible hat: disposed within a conventional pressurisahle metal outer casing, (widely ret'erred to as a Harrier pack system''). 'I'he flexible hag holds the liquid and is connected to the dispcusing valve of'thc container. while a gas under pressure is held within the outer casing'and outside the hag. which is substantially impcrmeahie. When the valve is operated.

the prcssurised gas compresses the flexible bag. expelling the liquid therein through the valve. Since the valve can he made entirely of plastics materials the liquid is never in contact with metal.

Nevertheless. such containers are generally unsuitable for anaerobic compositions. as there is no t'ree air volume in the bag to keep the liquid therein oxygenated.

An attempt has been made to address this problem in International l'atent Application No. WO 0()/18661- in which the flexible hag comprises a polymer permeable to oxygen, and the pressurised gas Outside the hag contains a significant level of oxygen. Thus an anaerobic composition within the hag can be stored without curing for substantial periods.

Unfortunately. it has been found that such a container still does not reliably dispense its entire contents. 'I'he hag often collapses unevenly' for example delivering material from adjacent the valve and then becoming locally constricted preventing delivery of material from a side of' the constriction remote l'rom the valve.

A similar problem is known in conventional barrier pack systems having impermeable bags' and it has been addressed for such systems in IJ5i latent No. 4148416. In this. a tubular body is placed within the flexible hag. leading prom an end thereol'adjacent the valve to adjacent a l'ar end. 'I'hus. even il' the hag becomes locally constricted. a passage is maintained past the constriction allowing material from the remote end ol' the hag to reach the valve.

Such an arrangement has unfortunately provecI an hiadequate solution to the problem for anaerobic compositions. 'I'o avoid collapsing inwardly under pressure. the tubular body has

relatively thick walls and hence a relatively narrow bore. This is especially true when the tubular body is of plastics material. as needs to he the case t'or most anaerobic compositions.

Such a narrow bore does not allow l'rec passage tor liquids or pastes as viscous as the majority ot'anaerohic compositions. 'I'he narrow openings at each end ot'the tubular body are prone to hlockape. I'urtilennore. even when combined with the oxyt,en-permeahle hag, of WO 00/18661. the interior ot'the tubular body is relatively inaccessible to oxygen permeating through the hulk ot'the composition. and so any ot'tile composition retained therein for any length ot'time will hegin to polymerise and can easily blocl; the bore. This is found to be the case even with versions ot' the tubular body having perforated walls, also shown in US 4148416.

lJS4148416 also discloses. as an alternative. an elongate solid body provided with longitudinal surt:ace ribs, but the passages defined between the ribs. the body and a constricted bag can often become too narrow to allow sufficiently tree passage of a viscous liquid or paste. Nevertheless, the concept ol' maintaining a passage loom end to end of a compressed bag appears sound.

It is hence an object of the present invention to provide a container in which an anaerobic composition may he stored and l'rom which it may be substantially completely dispensed.

providing the henet'its ot' the containers described above while obviating the problems described. Accortling'to the present invention. there is provitictl a dispenser t'or anaerobic compositions conprising cashed means adapted to withstand htcrnal pressure. flexible container means disposed within the cashed means and having \\alls permeable to oxygen and dispensing

valve means connected to the fioxibie container means and selectively operahie to release material held thcrewithin. wherein the dispenser is provided with elongate channel-det'ining means extending across an interior ot'tile tlexibie container means from adjacent the valve means to a remote end. the chanacl-defining means comprising solid wall elements extending :eneraliv radially out\ardly from its longitudinal axis and twisting to define at least one helical channel means extending generally longitudinally ot'the channel-defining means and connected along substantially its entire extent directly to an interior of the flexible container means. The channel-defining element may comprise a plastics material.

Preferably. said channel means comprises at least half of the area ol' a transverse eross-

section of the channel-det'ining means at any point thereof'.

Advantageously. there is a plurality of said channel means. each extending generally longitudinally ot' the channel-det'ining means. and optionally intereonneeted one with another. Preterably. the channel- defining means comprises a plurality of substantially identical t'irst sections arranged substantially along its longitudinal axis Advantageously. the channel-det'ining means also comprises a plurality of' second sections.

each substantially identical one to the others. and also arranged substantially alone: the longitudinal axis ot'tilc channcl-detining, means.

Said ftst and second sections may be arranged alternately along said longitudinal axis.

Prel'erahiv. each said first or second section defines at least one generally helical channel means extending pcneraliv kngituddialiv ot' the channel-defining means. optionally two gcncrallv helical channel means.

Advantageously. each said first section defines at least one channel means extending helically in an opposite sense to the at least one channel means defined by each said second section. leach said first section may thus define a clockwise helical path while each said second section det'ines an anticloclwise helical path. or vice versa.

Advantageously. said wall ol' each section is discontinuous with the corresponding wall of each adjoining section.

Each ot' the two helical channel means defined by each section will then be connected to each ot'the two helical channel means del'ined by each said adjoining section ()ptionally adjoining sections may he so disposed. one relative to the other. that their respective walls extend substantialiv at right angles one to the other where they meet.

Prcl'crahl!. each said t'irst or secont1 section defines helical channel means having a pitch ol' hetv\ccn one cluartcr and loser times a diameter ol'thc section

Advantageously. each said first or second section defines helical channel means having a pitch ol'betweer1 one hall' end two times said diameter. optionally having a pitch substantially equal to said diameter.

I'he flexible container means prelerahiv contains an anaerobic composition. such as an anaerobic curing adhesive or sealant material.

The dispenser advantageously contains a pressurized gas, held between the casing means and the flexible container means.

Said pressurised gas may comprise oxygen, and optionally may comprise compressed air.

An embodiment ot' the present invention will now be more particularly described by way of example and with reference to the accompanying drawings, in which: Figure 1 is a side elevation of a dispensing container embodying the invention, shown partially cut away: Figure 2 is a side elevation ol'a chamelling element -'t'the container of Figure 1, isolated therefrom: Figure is an axial cross-sectional vie\\ of the element ol'I:igure 2 taken along the line lit -- ||1: Figure is an axial cross-sectional view ol' the element of l'igure 2. taken along the line IV - IV: Figure HA is a scrap vie\\. he partial cross-section. Lila valve ol'tile container ol' 1:igti 1:

Figure SIB is a scrap view. in partial cross-section. of the valve shown in Figure SA in operation; Figure 6A is a scrap view in cross-section of a,as-t'illing, arrangement ot' the container ot'Figure 1: Figure 6B is a scrap view. in cross-section. ol' the gas-tilling arrangement shown in l:igure 6A in operation: and Figure 7 is a side elevation ot'tile dispensing container of l:igure 1 in user shown partially cut awe>.

Referring now to the l:igurcs. and to Figure I in particular a dispensing container 1 i'o.

anaerobic curing compositions comprises an elongate cylindrical outer casing 2' within which is disposed an elongate flexible hag 3. 'I'hc outer casing 2 may be of metal such as tinplate or aluminium. The flexibic bag 3 comprises a plastics material, such as low density polyethylene, which is permeable to gases and in particular oxygen containing gases. An elongate channelling element 4 of plastics material is disposed generally longitudinally within the flexible bag 3. and is shown in more detail hi Figures. 2. 3 and 4.

The container I is provided at a t'irst end with a dispensing valve 5 ol'generally conventional form. shown hi more detail in 1 igures SA and 5B 'I'he valve S is connected to an interior of the tieible hag 3. 'I'hc valve S has a nozzle 6 extending outwardly theret'rom. coaxial ot' the container 1. which is provided with a thread 7. A tapering extension nozzle 8. provided with a corresponding' thread on an interior surfacer man thus he screwed on to the nozzle (.

I'he ticxibie ha=, contains, the element is tilled with an anaerobic ctning composition ') to he diSpCnSCtl from the container 1. h1 the torm ot'a viscous 1icluid or a tl\\ahie paste. A

propellant gas 1 () is heltl untler pressure within the outer casing 2 and outside the flexible hag 3. (Arrangements tor injecthic this gas 1() into the container I are shown in l igures 6A and (13). I he propcilant gas 1() has a significant oxygen content - compressed air is a convenient example. Because the tlexibic hag is significantly pen1leahle to oxygen. some oxygen tram the propellant gas 1() \sill pass through the flexible hag 3 t' contact the anaerobic composition '). An oxygen concentration \xithh1 the anaerobic composition 9 is thus estahlishetl and maintahed wilicil is sulticicnt to prevent or at least significantiv retard premature curing within the container 1.

The channciling element 4, as shown in Figure 2 comprises a plurality of helical sections 11, 12 each formed of a wall extending radially on troth sides of the longitudal axis of the element 4. Helical sections I 1 having a twist in one sense say clockwise, alternate alone; the clement 4 with helical sections 12 having a twist in the opposite sense say anticlocl;wisc.

Lach of the helical sections 11. 12 twists in a respective sense through half a revolution about the longitudinal axis ot the elongate element 4. I he wall at a first end 13 of each section I I, 19 extends at right angles to the wall at an adjoining second end 14 ot a neighhourinL; section 19. 11.

thus. ha leisure 3. a second end 14 of a clockwise helical section 11 is visible. with each surface ot the section 1 I spiralling away in a clockwise sees. as shown. I he first entt I 3 ot tile sections I 1 is just ()hSCUl'L'tJ. AS is tile;LJ join ulticlockvisc section 19.

In I:igrc 4. t;rthLn- Alpine thL same hL'IiCal section 11. a small portion ol each surface ot the scctio 11 is \isihic. sphallin a\\a! he a clock\\isc sense as tar as the first entl I ol the section 1 1 I he second cud 14 <11 the atijninint. anticlock\\ise I1LIICal section 12 extentJs at

right angles to the first eT1U lo Of the clockwise section 11. and each surface ot' the adjoining ITC&IICLLI section 1 ? can he SCCT1 SP;rIl1;T1L aW.IV IT1 aI1 aI1t;CIOCkVV;SC SCT1SC.

I'he radially outer edges ol'tile \\alls ot' the helical sections 1 1 12 thus et't'ectiveiv define a cvii'irical VOIUT11C filled h! tlc eleTle't 4 OTltiTUOUS hut illirect passages extend IOngitUL1ITrallV IrOm OT1C end to the other entl ol' the element 4. and said passages are also accessible throughout to material enteritig then1 t'rorn laterally ol' the element 4. Similarly.

Oxygen permeating through the composition 9 can easily reach any part ot'these passages.

preventing the formation of anoxic:-'nes in which the composition 9 may start to cure.

However. the passages are suf'fieiently restricted. unlike in some known elements, that a flexible wall ot'the bag 3 cannot be compressed sip, nifieantly into the Cylindrical volume defined by the element 4.

A further benefit ot' the shape ot' clement 4 shown is that (as Figure 3 makes particularly Clear), the volume of the solid structure of' each Section 1 1, 12 is only a small proportion of the volume dethed by the element 4 (here. about a quarter thereof! Thus, the longitudinal channels have a relatively high transport capacity Or material flowing therealong. 'I'he TllaTlTler in VlliCh the ChaTlTlelS meet and split again at the cuds 13. 14 ot'eaeh section 1 1. 12 erasures that anv blockage that maN still Coma can easily be try-passed I'he net surface area ot'thc cicnent 4 shown is also miniTlliSCd. italic is hnTnortant lair viscous licluids and pastes. as surface drag can sigTliticantiv hamper thei'- llo\\. It flow were restricted unduly. higiler conpressecl air pressures woukl he recluired within the outer easing tat LIl'.Ve talc c<ll11sitiklll t) <It, l tare c<1t.liT1eI- 1.1 tlleI-e.-e lilllits t<1 tile pl-ssLIres tll,lt cr1111111cI-ci.lil! ionic r>Itc! c.lsill:s Can N\itllst.Ll.

Althougl1 the shape ol'elcmetit shown might appear complex. it has no awkward undercuts and is therefore relatively easy to injection-mould throne a poker of' choice The shape of the elencnt is also particularly conductive to gootI to ol'the composition I'he dispetisitl valve ol'tilc coritaincr I is relatively conventional. as l'igure HA and 513 sho\\ 'I'hc tioxible hag 2 is mounted to the outer casing and the valve 5 by meatis of' a peened annular seam 15. such that the valve 5 is connected only to an interior ot'the bag, 3 containing the composition 9. and not to the cotilpresscd gas 1 () between the casing, and the bag, The nozzle 6 is provided with a bore IG. which is open at an end distal to the container 1, but is closed by a plate 17 at a proximal end. disposed within the bag 3 A plurality of ports 18 extend througl1 the walls oi'thc nozzle 6 adjacent the plate 17 The nozzle 6 is seated within a resilient hush 19 of' elastomeric material Nomially, as shown in Figure 5A, the plate 17 is held securely against a proximal end oi'the hush 19 by the pressure of' the contents ot'thc hag, 3 'I'he ports IX are blocked by an intcrio' surface of' the hush 19. such that nothing, from within the hag cat1 pass into and out ot'the nozzle 6 I'o operate the valve is. the no//lc 6 is displaced laterally (tot- cxampic with a tinertip). HI TIC n/zlc 6 cants over as sho\\t1 in l:iurc:13 opening a Passaic hetwocn the plate 17 and the hush 1') Icading to the posts I X I he prcssre ot gas I () in the outct casing compresses the hag 3. uterine the licluid/pastc composition 9 tht-'ugh the ports IX atid int<'thc bore I 6 ot the nO//iC 6. two \\hich it is dispensed ()ncc the nozzle (, is rcicased the resilicut hush 1') rctuts to v.Tlvc to its of iritl;Tl colirut.ttio' te- sclig tlTc v.Tlvc

The outer cashig 2 is lolled with pressurised gas]() before use. as shown in Figures (PA and (fly An end2() oi'tile CaShle. 2 remote From the valve 5 is sligiltiv dished. to help it withstanti internal pressure. An elastomeric scil:scalbig gronnct 21 is implanted h1 the disiled end 0().

and a gas hjection ncellc 2 is passed thcretilroull. (ias 1(). such as c'mpresseti airs is hijcctei through the needle 22 Kilo an hiterior ol'thc casing 2. and the needle 22 is then withtlravn thcronmet2lscalblgitsell'autonaticallN.

Figure 7 shows the container 1 ha use. The valve S has been opened by displacing the nozzle 6 and attached extension nozzle 8 From their rest position. 'I'he compressed gas 1() in the outer casing has partially crushed the flexible bag 3 and thus expelled much of the composition 9 held therewithin through the valve 5. As will i'retiuently occur, the bag 3 has not collapsed evenly. and a localised constriction 23 has Formed. However this constriction 23 cannot tighten any Further once it has contacted the channelling element 4. Thus, composition 9 held in a portion of' the hag 3 remote prom the valve 5 can still flow into the passages extending longitudinally ol' the element 4 past the constriction 23 and into a portion of the hag 3 from whicl1 it nlav tat,\\ to the Valve 5. I'ven should one helical passage become blocked or trilled hV the hag 3. the opp,sitc passage of that section should he available for Lo\\ ol composition throne the two passages ot the section below to the too passages of the sectional.1h\'L'. Almost.11 fit tile c<,siti ') all;! 11L'l1CC he tliscIlsc] tom tllc C1t.lillcl l: tills PHI! \\.Ist.gc will lo. tllc sIll.lil.lorUlt of cpositior ') still present s\ithiT tile p.tss. ges ot tile cat \\l tills ha. let's cL,ll.psec1 c<lllctl!.

Claims (1)

1. l-, ('LAIMbi 1..N dispenser for anaerobic compositions comprising casing

   means adapted to withstand internal pressure. Ilexible container nomads tlisposetl \\ithin the casing 11iC;iS.1 ll.Vill \\.lils pOtIll'.thl' l() t).\gCIl di.spe'sil votive ems C<l'.Ctc.d tat the flexible container means and selectively operable to release material held therewitilin anti elongate channel-defining means extending across an interior of the flexible container means l'rom adjacent the valve means to a remote end and comprising solid Hall elements extending gencrally radially outwardly from its longitudinal axis and twisting to define at least one helical channel means extending generally longitudinally of the channel-defining means and connected along, substantially its entire extent directly to an interior of the ticxible container means.

   9. A dispenser as claimed in claim 1. wherein the channcl-dciininL: element comprises a plastics material.

   2,. A dispeTlsLr as claimed in either claim 1 or 9. wherein saiti channel means comprises tat least hall ot the area oi a transverse cross-section ol the channel-dLlining means at ! l3'iiat llLc<,l.

   A dispenser as claimLtl in an! ogle ot the prLccding claims. wherein the channcl-

   dLIinh means CompriSL'S a pluralit! ol substantialiv identical first sections arranged substantial!! along its lonitudinal.xis.

   5. A dispenser as claimed in claiTl1 4. wherein the channel-del'ining means l'urther comprises a pluralit!,I'secontl sections. each substaTltiall! idLritical one to the others.

   rll also TT.U1gLLT subst.TTlti.ll! alolg tile loTlgituctil.l axis of tile cilaTlTlel-ctef ililg Illealls. (a. A dispeTlscr as claimed in claim 5. wilerLin said t'irst and second sections arc arranged alternate along said l,ngitudiTlal axis.

   7. A dispenser as clahiletl in either clahil 5 or elaiTl1 (lo wherein each said first or second SCCtiO'1 defines at least one generally helical channel means extending generally longitudinally of tile ehaTlneldel'ining means.

   8. A dispenser as claitncd in claim 7 wherein each said first or second section defines two generally helical channel meaTls.

   ). A dispenser as clawed its any one ol' elaiTlis to X wherein each said first section deliTles at least OT1C Channel means CXtendhlg hOlicallv hi an opposite sense to the at Icast OTle Cll.iTlTlei T1lC.TTlS Llelilcd he exert saict second Section.

   1(). A dispenser as claimed in clahil '). \\hereh1 the channel means of' each said first section del'inc a clocl\sise helical path \\hile the charmer means ol'eacl1 said second section del'ine an anticlocl;\\isc helical patil. or vice VCrSa.

   1 1. A (5ISI1L'I1SL'!.TS CI;;11TCLI in [TIT! talc Al cl;tilis X to lo. \\llcleil s.liLl \\;lil of cycle SCCtiOl is discontinuous \\ith the corresp<1ndhlU \\all Ill each ad shying section. So that each of

   the t\\o helical cham1cl means dethied h! each section will then he connected to each ol the t\\o helical channel noons deleted h! each said ad johlbl: section.

   1. A dispenser as claimed h1 clothe 11. \\herein ad John sections arc so disposed. one relative to the OtilCr. that their respective \Nalls extend substantial!! at right angles one to the otiler \\here the! nlCCt.

   I a. A disposer as clahncd in an! one ol ciahilS to 1 9. whCrC j1 caCI1 said first or second section defines helical channel means having a pitch ol hetvvoen one quarter and tour times a diameter ot the section.

   14. dispenser as claimed in claim 13, wherein each said first or second section defines helical channel means having a pitch of between one half and two times said diameter optionally having a pitch substantially equal to said diameter.

   I:. A dispenser as claimed in an! one ot the prCCCdhl claims. wherein pressurized gas comprising oxycn is held het\\een the casing means ant1 the flexible container IllC;lil S. 1(. A dispenser slhstantiall! as ticscriLcd herch, \\ith rclrcncc to the l igUICS ol the icct;tl! iffy tl. \\ isles.