CA2005782A1

CA2005782A1 - Apparatus and method for the self-levelling of liquid in a container and/or for the introduction of bubble-free liquid to a container

Info

Publication number: CA2005782A1
Application number: CA002005782A
Authority: CA
Inventors: Malcolm G. Bock
Original assignee: Technicon Instruments Corp
Current assignee: Bayer Corp
Priority date: 1989-05-30
Filing date: 1989-12-18
Publication date: 1990-11-30
Also published as: AU3742989A; DK193891A; AU645961B2; DK193891D0; IL92005A0; EP0474630A4; JPH04505048A; WO1990015333A1; EP0474630A1; ES2017885A6

Abstract

ABSTRACT
New and improved apparatus and method for the self-levelling of a liquid in a container to a precisely predetermined level, with a concave meniscus, are provided;
and comprise one or more capillary pathways operatively associated with the container and operable upon contact therewith by the liquid within the container to flow liquid out of the container until the liquid has assumed the precisely predetermined level within the container, and to provide a concave liquid meniscus at that level. New and improved apparatus and method are also provided to transfer completely bubble-free liquid from a liquid supply chamber to a container; and comprise one or more capillary pathways operatively associated with both the supply chamber and the container and operable upon contact therewith by the liquid in the supply chamber to flow completely bubble-free liquid therefrom into the container, which may also include the self-levelling means as heretofore described. Central support of a predetermined volume of an immiscible isolation liquid on the concave meniscus of the liquid in the container of the precisely predetermined liquid level is also disclosed.

Description

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BACRGRoUND OF T~ INYBNTIO~
1. Field of The Invention.
This invention relates to new and improved apparatus and method for the ~qelf-levelling of a liquid in a container to a preci~ely predetermined level with a concave liquid meniqcu~, and includes new and improved apparatus and metnod to in~ure that ~uch liguid i~ completely bubble-free;
all particularly adapted to use in contemporary, highly accurate automated ~ample liquid analyqi~ ~y~temsu 2. Description of The Prior Art.
Although a wide variety of ~elf-levelling liquid container~ are known in the prior art~ none are known which accomplish that function in accordance with the teaching~ of the apparatus and method o ~hi~ invention. Representa~ive of the known prior art qelf-levelling containers are those di~clo~ed in united State3 Patent 4,602,995 is~ued July 29,~
1986 to Mr. Michael M. Cassaday, et al for "Liquid Level Adju~ting And Filtering Device," and assigned to the a~signee hereof, and united State~ Patent 4,758,409 is~ued July 19, 1988 to Mr. Kenneth F. Uffenheimer for "Microsample Cup," and as~igned to the assignee hereof; with both of the same functioning to achieve self-levelling of a liquid in a contain~r essentlally at a level coincident with completa container liquid capacity by purposeful over-filling of the container and collection of ~he resultant liquid over~low in a surrounding overflow reservoir. More specifically, in 4,602,995, a separate liquid level a~justing device in addition to the 3tandard liquid contalner is required, and must be operatively in~erted into the latt~r to pump the liquld th~refrom into the device to overfill the same back lnto th~ container, t~ua leaving the liquid in the device at a p~ede~e~mined lcvel rela~ lve to the containe~ and coincident Wi~h tha capaci~y Oe the llqui~ level adju~tlng d~vice; whlle ln ~,758,409 dirQct ove~iiling o~ ~he microaamplo cup, which can be ~emewha~ diEælcUlt due to the . . , : , . :
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., extremely ~mall ~ize thereof, i~ required. Both United States Patents 4,602,995 and 4,758,409 do, however, clearly dl~close the provi~ion of a concave meniscus on the liquid at the predetermined liquid level; and ~,602,995 further clearly disclo~eq the emplace~ent and support on that concave liguid meniscu~ of a precisely predetermined volume or "len~" of an appropriate immi3cible liquid to minimize 3ample liquid carryover in instances wherein the liquid level adjusting device i~ u~ed in conjunction with ~ample liquid container~ in an automated sample liquid analy~is ~ystem a~ disclo~ed therein. Self-levelling of the contained liquid to a level essent:Lally coincident with full container capacity as disclo~ed in united State~ Patent~
4,602,995 and 4,758,409 can, however, prov~ somewhat problematical in the event of significant mechanical di~turbance o~ ~he container after that liquid level ha3 been achieved, with resultant liquid spillage from the container albeit into a surrounding overflow reservoir; lt bein~ clear to those ~killed in this art that the same would result in a "final" liquid level in the container below that desired.
United States Patent3 4,602,995 and 4,75~,409 are, in any event, totally devoid of any disclosure of the utilization of capillary action in the self-levelling of a liquid in a container.
United State9 Patent 4,515,753 issued May 7, 198S
to John L. Smith, Ph.~., et al, ~or "Integra;L Reagent Di~pen~er," and as~1gned to the assignee hereof, di3clos~s a reagent liquid dispensing well comprising a reagent liquid supply port, and operatively connectèd, gravity feed reagent liquid ~upply means; and operates upon aspiration o~ the re~gent liquid ~rom the di~pQnsing well to ~ l~vel which un~ov~rs th~ ~upply por~ ~o pe~lodically replenish the reag~n~ uid ~rom ~he gravlty ~e~d supply ~e~n~; thereby m~int~1ning the roagont l~v~l wlthln the dl3p3n31ng woll '.

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within a narrow range until the available liquid 3upply is sub~tantially exhau~ed. Thi~ pat2nt does clearly disclose the provi~ion of a concave meniscu~ on th~ reagent liquid in the dispensing well, and the central positioning th~reo~ of a precisely predetermined volume or "len~" of an appropriate immi~cible isolation liquid for ~ample liquid carryover minimization purposes.
United States Patent 4d 774,057 is3ued September 27, 1988 to Mr. Kenn~th F. U~fenh~i~er, et al, for "Dual Liquid Dispen~er Package" discloqes a reagent di~pen~ing well of essentially the same na~ure as that disclos~d in United State~ Patent 4,5159753 as described directly hereinabove; but wherein the periodic replenishment of the reagent liquid in the di~pen ing well i9 accomplished by periodic rotation of the dispen~er packag~ to feed the reagent liquid fro~ the ~upply means to th~ di~pen~ing well under the influence of the thusly generated centrifugal forces.
United State~ Patent 4,515,753 and 4,774,057 are again, in any ev~nt, totally devoid of the utilization of capillary action in the sel~-levelling of a liquid in a container.
; With regard to the introduction of a completely bubble-free liquid to a cont~iner, no particularly relevant prior art is known to Applicant; it being clear to those skilled in this art that conventional sample liquid stream debubblers as disclose~ ~or example in United State9 Patent 3,241,432 issued March 22~ 1966 to Leonard T. Skeggs, Ph.D.
for "Sequential Multiple Sample Liquid ~naly~is Systemr" and assigned to the assignee hereof, are not particularly appllcable to that task~ More speci~ically, such debubble~s ~unction to debubble a ~ample liquid stream, whlch had p~eviously heen p~upo~e~ully a1r-segmontfld ~or sample liquid ca~yov~r miniml~a~ion purpose3 a~ ha~ now long been ~tanda~d in the au~oma~ed 3Ucce~siVe sample liquld analy~i~

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art, prior to sample liquid introduction to the actual analy~i~ means 90 aB not to adversely affect the accuracy of the analysi~ re~ult~; and, as ~uch, would clearly have no applicability to the introduction of a completely bubble-free liquid to a container attendant the "Eilling" thereof.
Too, it is not certain that prior art debubbler~ of thiq nature would be fully effective to totally remove extremely small air bubblers a~ may be entrained within the sample liquid, as opposed to inter sample liquid segment air segments.
Prior art debubblers as exemplified by that di~closed in Unit~d StatQs Patent 3,241,432 are, in any event, totally devoid of any di~clo~ure of the utiliz~tion of caplllary action in the introduction of completely bubble-free liquid to a contalner.
The respective di~closure of Uni~ed States Patents 4,602,995, 4,758,409, 4,515,753, 4,774,057 and 3,241,432 are hereby incorporated by reference in the disclo~ure o this application.
OBJECTS OF THE INVENTION
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It is, accordingly, an object of my invention to provide new and improved apparatu~ and method Eor the ~elf-levelling of a liquid in a container.
It is anot~er object o~ my invention to provide apparatus and method as above which are operable to e~fect sel~-levQlling of the liquid to a precisely predeterminable 1QVQ1 in the container.
It i~ another object of my invelltion to provide apparatus and method as above wh~rein the precisely predeterminable liquid level may be 3ignificantly below the ~ull liquld capaci~y level o~ the container.
anothe~ object Oe my inven~ion to p~ovlda apparatua and me~hod a~ above which are operable to provlde a concave m~nl~cu~ on ~he liquid in the aontainer.
~ nother ob~ct o~ my invontl~n to p~ovide apparatur and mothod ar~ above which aro o~ extremely ~1mple .~ ' , ' .

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configuration and manner of operation, which requir~ no moving parts or liquid pumping or the likQ, but which operate in~tead in accordance with an lnherently occuri~g action between the liquid and the self-levelling means.
It i~ another object of my invention to provide apparatu~ and method a~ above which are relatively fast-acting.
It i~ another object o~ my inv~ntion to provide apparatus a~ above which are readily and economically ~abricatable in accordance with well known manufacturing techniques from commonly available, relatively inexpen~ive materials known to be 3uitable to the ta~k.
It i~ another object of my invention to provide apparatu~ as above which are, as a practical m~tter, economically dispo~able after but a ~ingle use.
It is another object of my inv~ntion to provide apparatu~ and method a~ above which are particularly adapted to the central ~upport of a predetermined volume of a liquid which i~ immiacible with the contained liquid on the concave meni~cus of the contained liquid at the predetermined level.
It is another object of my invention to provide apparatu~ and method as above which are particularly adapted to application to ~ample llquid container~ ~or use in automated ~ample liquid analysis ~y~tem~.
It i9 anothe~ object o~ my inventlon to provida apparatus and method as above for tha introduction o~
completely bubble-free liquid to a container.
It is another object of my invention to provide bubble-fre~ liguid introduction apparatus and method a~
above which are o~ extremely ~imple configuration and manner o~ operation~ and which require no moving parts or liquid pumpln~ means or ~he like, ~u~ which operate ln~ead in accordance wlth an inherently occurin~ action between ~he liquld and the bu~ble-~ree liquid lntroduc~ion me~n~.
anothfl~ objec~ o~ my inventian ~o provide . :
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~35~2 bubble-free liquid introduction apparatus and method which are relatively fast-acting.
It i~ another object of my invention to provide bubble-free liquid introduction apparatus as above which are readily and economically fabricable in accordance with well known manufacturing technique~ from commonly available, relatively inexpen~ive material~ known to be suitable to the task.
It iB another object of my invention to provide bubble-~ree liquid introduction apparatu~ a~ above which are, as a practical matter, economically di~posable after but a single use.
It i~ another object of my invention to provide bubble-free liquid introcution apparatu~ and method as above which are particularly adapted to use in conjunction with the self-levelling apparatus and method of my invention.
It is a further object o~ m~ invention to provide bubble-free liquid introduction apparatus and method as above whicb are particularly adapted to application to sample liquid containers for u~e in automated sample liquid analysis systems.
SUMMARY OF T~E INVENTIO~
The invention comprises new and improve apparatus and method for the self-levelling of a liquid in a container to a precisely predetermined level, with a concave meni~cus;
and, as ~epresentatively disclosed here~n, take~ the Eorm of one or more ribs which form sharp-cornQred ~rface junctures wi~h the container ~ur~aces, and which ex~end contiguou~ly from the predetermined liquid le~el within the container at the interior container wall upwardly and acro~s the upper container edge or lip, and downwardly ~herefrom along the exkerior co~ainer wall to a l~vel on the la~e~ which 19 below the prede~ermln~d liquld level in ~he con~ainer~
Th~se sh~p-ao~nered rib~contain~r sur~aao ~uncturea ~orm con~iguou~ capillary pathway~ ~or capillary llquid ~low ;

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2~:)057a2 whicn are coextenaive therewith. The container and ribs are fabricated from a material which i~ readily wettable by the liquid in accordance with the formation by the latter of a contact angle of les~ than 90 with the ~ormer, thereby in~uring capillary ri~e of the liquid in the provided capillary pathway~. In uae, the liquid i~ conveniently introduced to the container to any practical level above the predetermined level thereby contacting and wetting the relevant portiona of the capillary pathway~, and thi~
result~ in the virtually immediate capillary ri~e of the liquid in tho~e pathway~ in re~ponse to the ~ame to commence liquid flow therein; with th~ head provided by the diEference in level~ a~ de~cri~ed ~unetioning through qiphon-like action to continue the same. Liquid flow out of the container continues a~ deaeribed in the provided capillary pathway~ until the level of the liquid in the container falla immediately below the level on the interior eontainer wall at which the sharp-eornered rib container ~urface juncturea, and thus the provided capillary pathway3, commence; thereby leaving the liquid in the con~ainer at the precisely predetermined level, and with a concave meni~cua thereon. ;
The invention ~urthar comprises new and improved apparatu~ and method for the completely bubble-free lntroduction of a liquid Erom a liquid ~upply chamber to a container which i~ not in ~ireet llquid flow eommunieation therewith; and, as repre~entatively disclosed hcrein, again eomprise one or more ribs which form sharp-eornered ~urfaee junetures, and thus capillary pathways a~ heretofore deseribed, with the respective llquid ~upply chamber and contalner aur~acea; and whieh, ln thi~ instance, extend eonti~u~u~ly ~rom a leYel in tha llquid ~upply chamber e~entially at ~lq bo~om th~r~o~ upwardly along ~he int~rlor chamber wall, aero3~ the upper 0dg~ ~r lip o~
common ~upply chamber and eontaine~ wall whlch divide~ the : ~ .
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~ame, and downwardly into the container along the interior wall to a level e~entially at the container bottom. The liquid supply chamber and the container are relatively di~po~ed ~o that the bottom of the chamber i8 at a lev~l above the full liquid level of th~ container. In use, the liquid is conveniently introduced to the liquid ~upply chamber to any practical level commen~urate with the liquid requirements of the container, thereby contacting and wetting the capillary pathways in the chamber, and this re~ults in the virtually imm~diate capillary rise of the liquid in tho~e pathway~ in respon~e to the ~ame to commence liquid ~low from the supply chambQr to the container; ~ith the head provided by the difference in levels a~ de~cribed functioning through aiphon-like ac~ion to continue liquid flow until sub~tantially all of the liquid in the supply chamber ha~ been flowed into the container along the provided capillary pathway~. Since gases cannot f:Low along capillary pathway~ by capillary action, completely bubble-free liquid, only, will be introduced a~ described from the liquid 3upply chamber to the con~ainer.
The inv~ntion further comprise~ th~ comblnation of the teachings of the new and improved bubble-freQ liquid introduction apparatu~ and mathod, and the new and improved self-levelling apparatus and method, both as heretofo~e de~cribed; and, as representatively disclo~ed herein takes the ~orm of a unitary container asqembly which includes a liquid supply chamber, a container, and an exce~a liquid collection chamber, with capillary pathways provided as described to extend re~pectively from the liguid ~upply chamber to the container, and ~rom essentially the pr~dfl~ermined liquid level in th~ container ~o the bottom 0 tne li~uid collqction chamber at a level balow the level o~
~he bott~m o~ ~he con~ainer~ ~n thl9 in~tance, ~he volume oP the ~upply chamber i~ predetarmlnad to bq grqater than tho volume o~ ~he contaln~r to ln~ure ~u~i~lclent llquid ~o . . , ~ .
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, "~ill" the latter to the de~ired predetermined level. In use, the liquid iq conveniently introduced to the supply chamber, and flowed therefrom as described along the provided capillary pathways, comple~ely free of bubble content, into the container; with the excess liquid flowed in turn along the provided capillary pathways from the container to the collection chamber; thereby ultimately resulting in the liquid which i9 retained in the container residing therein at the preci~ely predetermined level, and again with a concave meniscus.
Representative use of the apparatus and me~hod of the invention in an automated, ~ucces~ive sample liquid analysis ~ystem i~ also disclosed; in which instance the liquid would be constituted by a ~ample liquid. For such use, the central 3upport of a predetermined volume of an immiscible i~ola~ion liquid on the concave meniscus of the liquid in the container i9 al90 di~clo~ed for purpo~es of minimization of sample liquid carryover attendant succe~sivQ
sample liquids analyse~.
:~ DESCRIPTION 0~ T~ DRAWINGS
The above and other ~ignificant object~ and advantages of my invention are believe made clear by the following detailed description thereof taken in conjunction with the accompanying drawings wherein:

:~ FIG. 1 is a perspective view of a container ` operatively incorporating therewith new and lmproved liquid self-levelling means representatively configured and operable in accordance wi~h the teachings of my invention;
FIG. ~ is a top plan view of the container o~ FIG.
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FIG~ 3 iA a cro~ ecitQnal view taken e3~entially ~l~ng 1 ine 3-3 in F-L~J. 2;
,~ FIG. a~ iS an enla~ed ~ragmen~ary view of a por~ion o~ FIG. 3;
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FIGS. 5 nd 6 are re~pectively cro~s-sectional views as in FIG. 3, and re3pectively illustrate the operation of the ~elf-levelling means of my invention essentially at the commencement and completion thereof;
FIG. 7 is a top plan view of a container operatively incorporating the self-l~evelling mean~ of my invention, and excess liquid collection means~ therewith;
FIG. 8 iq a cros~-~ectional view taken e~sentially along line 8-8 in FIG. 7, and illu3trates the operation of the self-levelling mean~ of my invention essentially at the commencement thereof;
FIG. 9 i9 a cross-sectional view as in FIG. 8 illustrating the operation of the self-levelling means of my invention at the completion thereof, and further illustrates a representatlve application of the self-levelling means of the invention to u e in conjunction with an automated sa~ple liquid analysis sy~tem;
-FIG. 10 is a perspective view of a container operatively incorporating the self-l~velling mean~ of my invention, and new and improv~d bubble-free liquid ~: introduction means representatively configured and operable in accordance with the teachings of my invention, therewith;
FIG. 11 i3 a top plan view of th~ container of FIG. 10;
FIG. 12 iB a cross~sectional view taken essentially along the 12-12 in FIG. 11 and illu~trating the operations o~ the ~elf-levelllng and bubble-free liquid introduction means of my invention intermediate the ~ame;
and FIG. 13 is a cross-sectional view a~ in FIG. 12 and lllu~trating the operation~ Oe the ~al~ lev~lling an~
bubble-~ree liquid in~roduction mean~ o~ my invention at ~he completion thareo~.

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_ETAIL~D DE5CRIPTION OF T~E INVENTIO~
Referring now to FIGS. 1, 2, 3 ~nd 4 of the application drawings, an essentially conventional, open-topped fru~to-conical container is shown at 10; and includes new and improved self-levelling mean~ representatively configured and operable in accordance with the teaching~ of the currently contempla~ced best mode of the apparatus and method o~ my invention aq indicated generally at 12.
The ~elf-levelling mean~ 12 comprise es~entially identical container ribs as indicated at 14 and 16, and which are respectively disposed a~ shown to oppo~ite ~ide~
of the container 10 to be diametrically oppo~ed relative thereto.
Each o the ribs 14 and 16 i8 formed as ~hown to commence at, and to ~e flu~h with/ the interior side wall 18 of the container 10 at preci3ely the same level 20 within the containerj and ~o extend therefrom up and across the container top wall or lip 22, and down the container exterior ~ide wall 24 to terminate as shown e~3entially at the container bottom 26. To this efEec~ with regard to the co~mencem~nt of the cib~ 12 and 14 at preci~ely the same level 20 on the container interior side wall 18, the latter will be seen to be uni~ormly bevelled, as shown at 28, commencing at the level 20 and extending upwardly to tha top wall or lip 2,2 of the container 10.
With the self-levelling means 12 of my invention configured and dispo~ed as de~cribed relative to the container 10, it will be clear that four contiguous rib-contalner surface juncture~ or corners will be provided to re~pectlvely extend coexten~ively with the ribs 14 and 16 as descrlbed, on the basi~ o~ two contiguous rib-container ~ur~ce ~unc~ure~ or corner~ re~pec~ively to el~her side of ~e xib, Ero~n withln the contain~r 10 at ~he level 20 up and accr~3 the container lip 22 an~ downwardly there~rom on the exterior o:~ the container e~sen~ial~r to the c~ntainer ' ~ ' ~
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bottom 26.
More ~peciEically, and for rib 14, these contiguous rib-container surface junctures or corners, which are in each instance formed by the juncture of the rib aurEace with the respective surfaces of the bevelled container interior wall portion 28, the container lip 22, and the exterior container wall 24, are indicated at 30 and 32, re~pectively, to either side of the rib: while, for rib 16, these rib-container surface junctures of corners, ~ormed a~ de~cribed for rib 14, are indicated at 34 and 36, re~pectively, again to either side of the rib. For purposes of my invention aB described in detail hereinbelow, these rib-container surface junctures or corners 30, 32, 34 and 36 are made as sharp as practical in accordance with the particular material(s) chosen ~or the container 10 and the rib~ 14 and 16, and the particu}ar manufacturing technique(a) e~ployed in the fabrication thereof; it being noted in this regard ~ha~ a juncture or corner radius a~
indicated at R in the enlarged fragmentary view of FIG. 4 for corners 34 and 36 of 0.002 inch radiu3 maximum ha~
proven sati~factory in these regards.
In accordance with the teachings of my invention, it has been discovered that the contiguou~, sharp-cornered ; ri~-container surface junctures 30, 32, 34 and 36 will, under appropriate container material surface energy vi~-a-v contained liquid surface tension conditions as described in greater detail hereinbelow, functlon as micro-capilarry ~ubes, thu~ providing four capillary pathways a~
respectivQly formed by surface juncture~ 30, 32, 34 and 36, and which extend in each instance as heretofore described Eroln level 20 in~ide o~ container 10 upwardly and acros9 ~he aon~ain~r .llp 22 and downwardly ~here~rom essentially ~o th~
bo~om 26 0~ contalne~ lO; With e~ch o~ tho~e capillary pathway~ being inh~rently ~e~ec~ive unde~ the ln~luence o~ a c~n~ain~d llq-l1d drivlng ~orce a~ provlded b~ capillary rise ~' :
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to ~low liquid contained in container 10 above the level 20 out of thQ container, ther~by low2ring that liquid preci9~1y to that level within the container 10. In addition, and again in accordance with the teachings o~ my invention, it has been discovered that thi~ capillary action will inherently provide a concave meniscus on the contained liquid at preci~ely the level 20 within the containe.r 10 concomitantly with the lowering of that liquid to that level.
With more specific regard to the essential relation~hip~ between container mat2rial surface energy, contained liquid surface ten~ion, and capillarity, it will be clear to tho~e skilled in thi~ art thatr under conditions wherein extraneou~ forces arQ negligible, a particle of unconfined liquid will assume a perfectly spherical shap~
because o~ the attractive force~ between the respective liquid molecule9. In the interior of the unconfined liguid particle, each molecule i~, of course, surrounded by many others; and, on the average, the attractive force3 on each of those molecules are uniform in all directions. At the surface of the unconfined liquid particle, however, there is virtu~lly no outwardly directed attractive force to balance the inwardly directed attractive forces ~ince, for example, w.ith the unconfined liquid particle surrounded by air, there are relatively few molecules surrounding the same. Thua, the molecule~ at the 3urface of the liquid particle are subject~d to an inwardly directed force, whil~ the molecules near but not at the particle ~ur~ace ara al90 subjected to an inwardly directed force, although o lesser magnitude.
It therefore require~ a certain amount of work to bring a molecule ~rom the center of the spherical liquid particle to point near the particle sur~ce. Wh~n ~he volume o~ the uncon~in~d liquid p~rticl~ is lncrea~ed, as by ~he int~odllatl~n o~ more liquid ~herc~o, m~locule~ will have ~o b~ moved ~rom ~he in~erlor o~ the ~pherical particle to ~he 73 ~

p~rticle sufface to a~ nt ~or the increased sur~ace area there, thus requi~ing the performance of a certain am~unt of work; with the energy required for the same being propo~tional to the increa~e in ~ur~ace area. Thi~ energy, which i~ expre~sed in term~ of work per unit area as the units of fo~ce per unit length, i9 called ~urface tension.
Sur~ace ten~ion will always exi~t whenever there i~ a den~ity discontinuity at an interface, for example the air-liquid interface between an uncon~ined liquid particle in air; with the magnitude of the ~urface ten~ion being dependent in that in~ance upon the dLfference in densitie~
between air and ~he liquid in question. A particularly important a~pect of surface ten~ion is the fact that it create~ a pre~ure change across an interface whenever that interface is curved, thus leading to the phenomenon of capillary rise; it having proved conve~ient to calculate the magnitude of the pre~sure change in accordance with the concept of s~urface ten~ion. For an unconfined spherical liquid particle in air, this pre~sure change may be calculated in accordance with the following Equation I:

~ P = pi = ~ po = 26/r wherein, aP i8 the pressure change, pi is the pres~ure at the interior of the liquid particle po is the air pressure outside the liquid particle, is the sur~ace tension of the liquid, and r i~ the radiu3 o~ the spherical liquid particle.

In addltion to the abova, i~ W11l b~ readily under~o~d by ~hose ~killod in this ar~ that, when a drop aE
liquld ls placqd on a solid sur~ace and 8u~rounded by air, the inte~eace between tho liquid drop will be lnclined ~t : ~ .
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some angle to the solid surface. This angle i9 known as the wetting angle or contact angle and is generally indicated by the term "theta." This wetting or contact angle depend~
basically upon the relative attractions of the molecules of three media involved, in this instance, the liquid, the 901 id which forms the suppor~ing surface, and the surrounding air, and is therefore a function of the relevant physical characteristics of all three of the~e ~ubstances.
In addition, this angle i9 i~ very ~ensitive to contaminants, and is dependent in part upon whether the liquid i9 advancing or receding over the ~olid supporting ~urface.
These phenomena of surface tension, pre~sure change, and wetting or contact angle, may be understood to be those which result in the ri~e or fall of a liquid as occur when a small diameter tube .i9 dipped into the liquid;
it being noted that when the ri~e or fall of the liquid is much larger than the radius of the tube, the interface or meniscus separating the liquid from the ~urrounding medium, normally the ambient air, may be assumed to be nearly ~pherical, and the extent of the liquid ri3e or fall relative to the tube closely approximated in accordance with the ~ollowing Equation II:

h = (2~/gr~ X cos(theta) wherein, h is the extent of the ri~e or fall of the liquid, is the surface tension of the liquid, g i~ the acceleration Oe gravity, r is the radius of t~e tube, i9 ~he den~ity of the liquid, and ~heta i8 t:he con~act anglo betweerl the liquid ~nd ~ha ~.ube~, Careeul examination o~ Equation II rovaals ~hat .
. . : . . .

the 2~/r term i~ pres~ure change 4P acro3s the liquid-air interface as calculated in accordance with the 3urface ten~ion of the liquid and the radius of the interface ~rom Equation I; while the co~(theta) term i~ derived from the contact an~le of the liquid with the tube in accordance with the relative attractionq of the molecules of the three media involved, namely the liquid, the surrounded air, and the qolid material of the tube. If the liquid molecule3 are attracted to the solid tube material molecule~, the contact angle at the liquid-tube interface will be les~ than 9o degrees to result in a po~itive c09( theta) ter~, and an attraction or ri3e in the liquid level in the tube. This will al~o result in concave meniscus for the liquid. If, on the other hand, the liquid molecules are repulsed by the molecule~ of the ~olid tube material, the contact angle at the liquid-tube interface will be greater than 90 degrees to re~ult in negative co~(theta) term, and a repulsion or fall in the liquid level in the tube. In this in~tance, the meniscus of the liquid in the tube would be con~ex. The applicability of Equation II to approximate liquid ri~e or fall in a tube is limited tyo ~ituations as described wherein the density of the ~urrounding medium i9 much le than the den~ity of the liquid.
With the above in view, re~erence may now be had to FIGS. 5 and 6 of the application drawings eOr detailed description o~ the operation o~ the self-levelling means 12 of my invention in conjunction with the contalner 10; it ~eing under~tood that such description is in accordance with the containment o a liquid a~ indicated at 40 in FIGS. 5 and 6 which ~orms a wetting or contact angle of le~s than 90 degree9 with the material~ o~ the container 10 and the rib~
1~ and 16.
FIG. 5 lllu~trate~ the ~1ling o~ ~he corltalner 10 ~ub~antially to capacity at the contalner lip 22 with the 1 Iquld 40, fo~ example by the simple manual pour.ing o~ ~he ' , ~ .
.
.
.

.
- . ,, ~. - ~ .

.

~)5~7 liquid thereinto. In in~tances wherein liquid 3pillage over the container lip 22 i~ of no con~equence, or wherein additional provision i~ made for liquid ~pillage containment externally of the container 10 a~ de~cribed in detail hereinbelow, filling of the container to capacity as illu3trated in FIG. 5 may be readily accomplished by simply pouring the liquid thereinto until the liquid perhaps ~lightly overflows the container lip 22 thus in~uring that the container is full; and thia, o courser negate~ any reqeirement that the liquid 40 be initially introduced to the container 10 With any degree of time-consuming preci~ion and care to "fill" the container to any predetermined level.
With the container 10 filled to capacity by the liquid 40 a~ illustrated in FIG. 5, it will be clear that a convex meniscu~ as indicated at 42 will initially be formed by the liquid.
Filling of the container 10 with the liquid 40 a~
shown in FIG. 5 will, of course, re~ult in the immediate wetting by the liquid o the contalner interior, including tho~e portions of the capillary pathways formed as de~cribed by the rib-container ~urface junctures 30 and 32, and 34 and 36, reApectively to opposite side~ of the ribs 14 and 16, which are within the container 10 and coincident with the bevelled interior container wall portion 28; and the virtually concomitant commencement in each in~tance o~ th~
~low oE the liquid 40 under cap~llary action as described essentially at right angle~ to the juncture radii R along tho~e capillary pathway~ upwardly ~rom the interior of the container 10 acro~s the container lip 22 and downwardly along the exterior of the container 10 es~entially to the aon~ain~r bottom 26; with the pressUrq drop o~ "head"
bq~ween ~he h~igh~ o~ wha~ becomes ~he sourco llquld 90 in cQn~ainer 1~ above kh~ level ?.0~ and ~h~ heigh~ o~ the container bottom 26, ~Unationing to provide a siphon e~ect ~:o maint~in ~low o~ the liquid ~0 along the capillary ,;. :' : .

.

~5~82 pathwayq. Thi~ is to say that, once ~low o~ the liq~id 40 ~rom the container lO in the c~pillary pathway~ focmed by rib-container ~urface juncture~ 30, 32, 34 and 36 i~
commenced a~ de3cribed by capillary ri~e up and acroqs the container lip 22 and down the container exterior, thi~
~iphon effect will operate to in~ure the continuation of the ~ame along tho~e capillary pathway~. Liquid flow i9 ~hown by the flow arrows in FIG. 5.
Flow of the liquid 40 along the ~harp-cornered capillary pathway~ provided by the rib-container surface juncture~ 30, 32, 34 and 36 from the container interior will continue a~ de~cribed until the liquid level in the container drops ea~entially to --in reality an extremely qhort distance below-- the level 20, as illu~trated in FIG.
6, at which liquid level flow will, of course, cea~e since there i~ no longer any liquid present at what are in ~s~ence the inlet3 to the capillary pathways at the points where the ri~s 14 and 16 re~pectively become flush with the interior container wall 18. In addition, and aq also clearly lllu3trated by FIG. 6, the meniscu~ 42 of the liquid 40 in the container lO will be flipped from convex to concave in accordance with the wettin~ of the container and rib material(~) by the liquid and the phenomenon of capillary rise as de~cribed, attendant this redu~tion in liquid level e~sentially to the level 20 in the container 10. ~hus, and in ~u}l accordance with the stated objec~s o the apparatus and method of my invention, it will be immediately clear to tho~e skilled in thi~ art that the level of the liquid 40 in the container 10 i~ inherently fixed at a precisely pradeterminable level in the container~interior below the container lip and vi~tually colncident with the ~xtent o tha ~ 14 and 16 into khe container in~erior~ and that the liq~id 4~ Will lnherently exh~bit a concave meni3cu~ a~ tha~
levql; all totally without requ1rement~ ~or any p~rticular degree~ Oe ~kill, preci~ion, care, o~ time expenditure~, in . .
. , ... ; . ~:
,, ~
' .
'. ' `. .~ :'~ ,' '.' ' ~3q)57~2 the inltial ~illing of the container 10, for moving parts, or toc the conduct o~ operations of any nature beyond the relatively 9imple initial filling of the container a~
de~cribed with the liquid 40.
A container a~embly representatively configured and operable in accordance with the teaching~ of the apparatus and method of my invention for u~e in automated, ~uccessive sample liquid analysis ~y~tem3 oE the type hereto~ore de~cribed with regard to United State~ Patents 4,602,995, 4,678,641, 4,758,409 and 4,774,057 is indicated generally at 50 in FIGS. 7, 8 and 9; and will im~ediately be ~een to compri~e the container 10 with th~ self-levelling means 12 as again ~ormed by the ribs 14 and 16 configured and operatively associated therewith as heretofore descri~ed, The container asaembly 50 further includes an ou~er container member 52 joined as illu~trated from the outer surfaces 54 and 56 of the riba 14 and 16 to the container 10 to be spaced from and surround the same at the container sides and bottom. Thi~ provides arcuate liquid flow passages as indicated at 58 and 60 between the exterior ~ide wall 24 of the container 10 and the interior side wall 62 of the outer container member 52, as divided by the ribs 14 and 16, and provides a liguid collection ~pace 64 ~etween the exterior wall 66 of the bottom 26 of the container 10 and ~he interior wall 6~3 of the bottom 70 o~ the ou~er container member of the outer container member 52; it being immediately clear that the liquid collection space 64 will be in liquid flow communication with each of the Elow pa~sage.s 58 and 60, and with each of the capillary pathways which are ~ormed as de~cribed by the sharp-cornered rib-container ~urface junctures 30, 32, 34 and 36, re9pectively.
In addition ~o thQ above, i~ will be c:lear tha~
~he ou~er con~ner rnember 52, which preeerably extenda a~
seen ln FIGS. 8 and 9 ~ome di~nce above ~he ~op sur~ace9 70 and 72 o~ the rib~ 14 and 16, can Eunction to ,,`
.

. . ~. . , . ~ . .
.

- - : .
~ . . . .
- . . . -r~

advantageously Eacilitate handling of the container a3sembly 50, and the operative emplacement thereof in ~ample liquid analysi~ sy~tem container indexing mean~ by pre~enting a ~mooth and uniform surface Eor the assembly; and/or to render more ef~ective the operable emplacement o a suitable evaporation cover to inhibit sample liquid evaporation over one or more of the container assemblie~ by effectively preventing contact by the ambient air with the ~ample liq~id ~uface(s).
FIG. 8 depicts the container ass2mbly 50 of my invention immediately upon the completion of the simple filling of the container 10 as heretofore de~cribed es~entially to capacity with a sample liquid, a~ indicated at 76, including an initially convex meni~cus a3 indiacted at 78; and make~ clear that, within reason, any ~pillage of the sample liquid 76 as may have occured during the filling of container 10 and overflowed the same will have been effectively contained by the upper wall portions of the outer container member 52 which extend as shown above ~he lip 22 of the container lO for downward flow through arcuate flow passage~ 58 and 60, and containment a~ representatively illu~trated in the collection space 64.
FIG. 9 depicts the container assembly 50 upon the completion of the flow of that portion of th~ sample liquid 76 in container 10 above the level 20, up and out o~ tha container interior, across the lip 22, and down the container extQ~ior, along the rQspective capLllary pathways toemed by the sharp-corne~ed rib-container surface junctuces 30, 32, 34 and 36, all aY heretofore d~scribed in detail with cegard to FIG. 6, with attendant ~llp o~ the sample liquid meni~cus 78 ~rorn convex to concave; and FIG~ 9 makes imme~ia~ely clear ~hat ~his port:lon o~ the s~mple llguid 76 will also be con~ain~e~ in ~he collec~ion space ~ aa illustrate~ along wl~h the sarnple liquid ~pilla~e, i~ any, upon ~he i~low o~ ~hat llqllid por~ion into that collection ~',, .

.. . " ' ', ' ' ' ! ~ , : -, . -- : ~ :
, ' . ' ' ' ' : - ' , ' . : :
'~ , '. , ~ :

3 S 7 ~ ~

space from thoae capilldry pathways as indicated by the sample liquid flow arrows in FIG. 9 at the lower extremitie~
of those capillary pathway~.
Under all of the above circum~tances, it will be clear that, again within reason with regard to the initial filling to capacity of the container 10, no contaminating leakage of the ~ample liquid 76 from the container a~qembly 50 of my invention ~hould occur; and this will be readily understood by tho~e qkilled in this art to be of particular contemporary importance in those instance~ wherein the ~ample liquid 76 i~ constituted by a biological liquid which may contain highly and readily communicable infectious agent(s).
With the level of the sample liquid 76 in the container 10 of the container assembly 50 e~sentially coincident a~ illustrated and de~cribed with regard to FIG.
9 with the level 20, and thus at preci~ely the same readily reproducible level in each of the plurality of the container assemblies 50 as would be employed in an automated, successive sample liquid analysi~ sy~tem as heretofore described, it will be readily apparent to tho~e skilled in thi~ art that successive ~ample liquid presentation~ to the preci~ely operable 3ample liquid analysi~ ~ystem probe means, as shown at 80 in FIG. 9, at preclsely the ~ame liquid level, ia assured. This, as de~cribed in ~ome detail in United States Patenta 4,602,995 and 4,758,~09, i9 of particular importance with regard to insuring precisQly the same probe residence time in the liquids 76 in each of the sample llquid container assemblie~ 50 a~ the pro~e meanY 80 are moved in each in~tance, under the control of probe means actuator m~ans as depicted schematically at 82 irl FIG. 9, ~r~m ~he probe meana po~ition depicted in phantom lines wherein ~he ~ame are wi~hou~ the sample liqL~ld containe~
~a3ambly 50, t~ kh~ probe moan~ po9iti~n d~picted in ~olid line~ wheFein the inlet end ~33 o~ the probe means i~

.
.
.
: ' .' ' . . ' : . . - ':

~ ~-- , ~ ~ ~ 5 ~ ~ ~d 1mmer~ed in the 3ample liquid 76 for sample liquid a~piration and qupply a~ indicated to the sample liquid analy~i~ sy~tem; thus in ~urn insuring the aspiration by the probe mean~ 80 and supply to the sa~ple liquid analy~i~
~ystem of preci3ely the same volume of sample liquid 76 from each o~ the succe~sively presented sample liquid container as3emblies 50; all to particularly ~significant advantage with regard to the overall and con~istent accuracy of the ~ample liquid analysis result~.
The probe means 80 may, for example, take the general form of those di~clo~ed in united State~ Patent 4,121,466 i~sued October 24, 1978 to Mr. Allen Reichler, et al for "Liquid Di~pen3er With An rmproved Probe;" in which instance the probe mean~ 80 would include mean~ to coat the sdme with a thin layer of an immi~cible isolation liquid a~
~et forth in ~ome detail in united State~ P~tent 4~121,466, the disclo~ure of which i3 hereby incorporated by reference in thi~ ~pecification.
In addition to the above, and with the meni~cu~ 78 of the ~ample liquid 76 in the container 10 of the container a~sembly 50 flipped as heretofore described to concave attendant the reduction of the level of the sample liquid essentially to the level 20, it will be clear that an approp~iate, predetermined volume oE an immi~cible i~olation liquid, or "lQn~" thereo~ as the same is commonly termed, as indicated at 84, may be emplaced in any ~uitable manner, for example by operatively as~oclated, precisely operable i~olati,on liquid dispenser means a~ indicated schematically at as in FIG. 8, on the concave meniscu~ 78 of the sample li~uid as ~een in FIG. 9; it b~ing clear that the isolation 1 iquid di3pen~e~ mean~ ~3S would only be oporable to emplace tho l~olatlon 11quld len~ ~ on the concavq liquid meni~cu~
a~e~ ~he same had come ln~o being, and prior to operation Oe the pro~e means 8~ a~ hereina~ter de~cribed ln dqtail.
~he ~ur~ac~ tension o the ~ample liqllld 76 will ~Unction ~o . ~ :

. . - : -, ,, , - . , ~ , -:

s~

retain the isolation liquld lens atop the meni~cus 78, and tne concavity of that meni~cu~ will function to retain the lens ~4 preci~ely certrally di~po~ed relative to the container lO, and thu~ relative to probe mean~ 80. Thus, and for use a~ de~cribed of a ~ucce~sive plurality of the container as~emblies 50 in an automated ~ample liquid analyqis system, and with the isolation liquid len3 84 constituted in each instance by preci~ely the same volume of the i~olation liquid, it will immediately be clear that precisely the ~ame thickne~s of the i301ation li~uid lens 84, and thus preci~ely the same i~olation llquid volume, will be pre~ented to the probe means 80 for aspiration therethrough preceding sample liguid aspirati.on upon mov~ment as de~3cribed of the probe means into the re~pective ~ample liquid~ 76 in each of the ~ucce3~ively presented sample liquid container a~emblies 50.
Although described in some detail in United State~
Patents 4,121,466, 4,515,753, 4,678,641 and 4,602,995, it i~
reiterated in this specification that, for uqe with sample liquids 76 which are e~sentially aqueous, the immiscible i~olation liquid, for example a fluorinated hydrocarbon liquid, functions to ~electively wet the hydrophobic analysi~ ~y~tem components, including probe means 80, to the ~ub~tantial exclu~ion of the aample 1iquids under analysis, thu3 sub3tantially preventing the adherence o~ those ~ample liquids to the analysi~3 ~yst~m components. This signiicantly reduce~ sample liquid "carryover," i.e. the contamination of the ~ucceeding ~ample ~iquid by the residue o~ a preceding ~ample liquid, with resultant maximization of th~ accu~acy o~ the 9ucce99ive sample liquid analy~i~
re~ult~ Thu3, ~ha provi~ion a~ d~cribed in accordancQ
wi~h ~he k~achlng.s o~ my Inv~n~.ton Oe precl~ely the ~ame volulne o~ khe l~ola~ion Ilquld erom len~ 3~ a~piration by probe mean~ ~o p~ace~ing the ~pira~ion in each in~tanc~
o~ the sample liquids 7~ in turn trom the succe~sively , ;' ' , . , :

2(~5~32 2~
presented container a~3emblie~ 50 i9 al~o of ~ignificant advantage in, on the one hand, in~uring that a predetermined, preci~ely ~ufficient volume of the i~olation liquid a~ required by the ~ample liquid analyAi~ ~ystem for the carryover minimization ta~k at hand for each sample liquid, i~ provided; while, on the other hand, in~uring that exce~ and wa~teful volumes of the isolation liquid, which are quite expen~ive and which can adver~ely afect the accuracy of the ~ample liquid analysi~ re~ults, are not provided.
A container asaembly representatively configured and operable in accordance with the teaching~ of the currently contemplated be3t mode o~ the apparatus and method of my invention for the accomplishment of both the ready and convenient, bubble-free filling of a container, and the sub4equent adju~tment in the level of the liquid in ~he thusly filled container to a preci~ely predetermined level a~ hereto~ore de~cribed in detail, i9 indicated generally at 100 in FIGSo 10~ 12 and 13 of the application drawin~.
Container a~embly 100 comprises a central, generally cylindrical container 102 in the nature of container 10 as hereto~ore described with regard to FIGS~ 1 through 9, and a generally cylindrical outer container member 104 which surround~ container 100 generally conc-entrically thereo~, and which is spaced therefrom as ~hown to provide a torou~-like space generally indicated at 106 therebetween. vertical dividing wall~ a~ indicated at 108 and 110 extend radially as shown between the respective side walls oE container 102 and oute~ container member 104 at a 180 interval thereby dividing space 106 into arcuate spacea 116 and 118. As best seen in F}G~ 10, the aide wall con~alner 1~ divided ea~en~ially along thq container diameter d~ 1ndicat~d at 1~0 tO eo~m semi~cylind~ical containe~ alde w~ll por~ions 122 and 124, with the ~ormer being o~ si~nieican~ly l~a~ hei~ht ~han ~he latte~.

.

.

`

." ' X~5~7~2 A generally semi-circular bottom wall 126 extends generally horizontally a~ ~hown between the higher container ~ide wall portion 12~, intermediate the same, and the side wall of outer container member 104 thereby forming, in conjunction with that container ~ide wall portion, the outer container ~ide wall, and the dividing walls 108 and 110, an open-topped arcuate liquid chamber 128, which is coincident with ~pace 116; while a generally semi-circular bottom wall 129 extend~ a~ ~hown generally horizontally between the lower edge of the lower container ~ide wall portion 122 and the lower portion of the side wall of outer container member 104 thereby forming, in conjunction with that container ~ide wall portion, the outer container side wall, and dividing wall~ 108 and 110, an open topped arcuate liquid chamber 130 which i9 coincident with space 118.
For reason~ made clear hereinbelow, :it i9 0 f particular inportance to the operation of the container a~aembly 100 of my invention that the level o~ bottom wall 126 o~ liquid chamber 128 be above the level of the uppar edge or lip 132 of the lower portion 122 of the side wall of container 102.
Automatically operable means for the ready and convenient, ~ubble-feee filling of container 102 with liquid and liquid chamber 128 are indicated generally at 13~; and take the ~orm of a ri~ 136 operatively a~sociated with both the container 102 and the liquid chamber 123 and which, in the manner hereto~ore described in detail with regard to rib~ 1~, and 16 o~ FIGS. 1 through 10, forms contiquous, ~harp-cornered rib--container ~urface junctureq with the co~tainer 102. More speci~ically, rib 136 extends a~ be~t seen in FIGS. 12 and 13 along the ex~erior surface o~ the ~ide wall p~rtion 12~ Oe conta1ne~ 102 sub~kantially ~rom ~h~ inker~ctloll Oe khe bot~om w~ll 126 o~ liquid chamber 128 ~he~ewlth upwardly as ~hown and over and across the upp~ edg~3 or llp Oe the contaln~ ~Id~ wall portlon 124, , :
. :

2~ 7~

and downwardly therefrom along the interior ~urface of that container ~ide wall portion sub3tantially to the bottom wall 140 of container 102; thereby forming contiguous rib-container ~urface juncture~, a~ reapectively indicated at 142 and 144 to either ~ide of rib 136, extending in each in~tance 3ubstantially from the bottom of liquid chamber 128 to the bottom of container 102. Thia, as heretofore de~cribed in ~ome detail, provides capillary pathwaya coextenaive with tho~e rib-container surface junctures for liquid elow from liquid chamber 128 into container 102.
Self-levelling mean~ configured and operable in accordance with the teaching~ of the method and apparatua of my invention ~or the automatic adjustment of the liquid level in container lO2 to a preci3ely predetermined level are indicated generally at 146 in FIGS. 10 through 13 and, in the manner oE aelf-levelling means 12 as heretoore described in detail with regard to FIGS. 1 through 9, comprise a rib 148, diametrically opposed to rib 136 vis-a-vis container 102, which again form3 3harp-cornered rib-oontainer ~urface juncturea with the container 102. More specifically, rib 148 exter!ds a~ best seen in FIGS. 12 and 13 from a preciaely predetermined level 150 on the interior surface of the ~ide wall portion 122 of container 102 upwardly aa ~hown and over and acrosa the upper edge or lip 132 thereof, and downwardly therefrom along the exterior surface of that container ~ide wa}l portion substantial1y to the bottom wall 129 of the liquid chamber 130; thereby forming contiguous rib-container surface junctureq 152 and 154 re~pectively to either s1de of rib 148i extending in each instance ~rom level 150 in container 102 subatantially to the bottom o~ liquid chamber 130~ and providing, aa hereto~ore de~cribcd, capillary pathways coextenaiva ~herewi~h eor liquld ~low ~rom level 150 in container 102 lnt~ ~he li~uid ahamber 130. r~G~ l2 and 13 make clear thak the levol 150 in container 10~ is ~igniEicankly above , ~ )5~

the level of the bottom 129 of liquid chamber 130; while FIGS. 11 through 13 make clear that the respective volume3 of liquid chambers 128 and 130 are, in each instance, greater than the volume o~ container 102.
In u~e of the container a~sembly 100 for the ready and convenient filling of container 102 e~qentially to the level 150 with completely bubble-free liquid from liquid chamber 128, and with the liquid in question of course being one which readily wet~ the container a~sembly material~ by forming a contact angle of le~ than 90 therewith a3 heretofore described, it may be under~tood that liquid chamber 128 i~ initially filled in any convenient manner, for example by the ~imple pouring or cli3pensing of a liquid a~ indicated at 156 in FIGS. 12 and 13 thereinto, alway~ to somewhat le~s than the full capacity thereof below the upper edge or lip 132 of container ~ide wall portion 124 to prevent overflow o~ the liquid 156 from chamber 128 directly into container 102; and this again ~akes clear as described in some detail hereinabove with regard to the initial filling of container 10 that no particular degree of skill or care need be exercised, nor inordinate amount of time ~xpended, in the initial filling of the chamber 128 with the liquid 156 to any precisely prede~ermined level. In addition, and to ~urther ~ignificant advantage a~ described in detail hereinbelow, it may be understood that, within reason, no care o~ any nature need be taken to inqure that the llquid introduced as describe~ to chamber 128 is at all bubble-free.
Immediately upon contact by the liquid 156 with the capillary pathways formed a3 herQtofore de~cribed in chamber 128 by the sharp-cornered rib-con~ainer surface ~uncture~ 1~2 and 144 to oppo~ite ~ides o~ rib 136, and the w~in~ ~her~o~ by the liquld, it will be clea~ ~h~ ~low o~
khe ll~uld 156 along tho~e capillary pathways ~rom liquld chamber 12~ in~o contalner 102 Will commonce in accordance '' ~ :

' X~ 78Z

with the head provi~ed by the difference in height between chamber 128 and container 102. Since the flow of air along the capillary pathways provided by rib-container 3urface junctures 142 and 144 i~ not po~ible, it will be readily understood ~y tho~e skilled in thi~ art that completely bub~le-free liquid 156, only, will flow aa de~cribed from chamber 128 to container 102; and thi~ de3pite the fact that the liquid 156 a~ initally introduced into chamber may very well contain some meaaure of air bubbles.
Immediately upon contact by the thusly flowed liquid from chamber 128 into container 102, and the contact therewith and wetting thereby o~ the capillary pathway~
formed by the rib-container ~urface juncture~ 152 and 154 to oppo ite side~ of rib 148 within container 102, it will be clear that flow o~ the liquid 156 along tho~e capillary pathway~ from container 102 to liquid chamber 130 will al90 commence in accordance with the head providecl by the difference in height between the container 102 and the chamber 130; thereby providing concomitant flow of the liquid 156 from chamber 128 to container 102; and from container 102 to chamber 130, re~pectively. FIG. 12 illu~trate~ thi~ ~tage in the operation of the container as~embly 100 o~ my invention; with the flow arrow~ adjacent the capillary pathway formed by the ~haep-corneced ~ur~ace juncture 142 o~ rib 136 with side wall portion 124 of container 102 illustrating the elow of liquid 156 from chamber 128 into container 102; and the flow arrow~ adjacent the capillary pathway formed by the ~harp-cornered surface juncture 152 of rib 148 with ~ide wall portion 122 o~
container 102 illu~trating the concomitant flow of the }iquid 156 ~rom container 102 to chamber 130.
operation o~ th~ con~ainer a~embly loo o~ my rlvonk~ton con~inue~ a~ de~cribed untlll all avallable liquid 156 erom chambe~ 128 ha~ ~lowed, to~ally without air bu~bl~
con~en~, in~e con~a~ner 102, and all av~tlable liquld 15~ ln ,~ . ,,~
., : .
.

: . . : : .

2~ 7~

contai~er 102 above level 150 haq ~lowed in turn from that container for collection in chamber 130; thu~, and in accordance with the provision of a normally anti~ipated "fill" volume for chamber 128 which i~ clearly greater than the volume of container 102 below level 150, insuring that, upon completion of all ~low of the liquid 156 as de~cribed, the container 102 will contain that liquid totally bubble-free, and at a level e~entially coincident with level 150.
FIG. 13 illu~trates thi~ final, irlsofar a~ flow of the liquid 156 i~ concerned, condition of the container a~sembly 100, and make~ clear thac the meniqcu~ 158 of the liquid 156 in container 102 will again be concave.
The container aqqembly 100 of FIGS. 10 throuyh 13 is pa~ticularly adapted for use as a micro~ample cup of the nature disclosed in united State~q Patent 4,758,~09 in an autolnated, succeqsi~ve sample liquid analysi~ syqtem. For ~uch u~e, and with the meniscu~ 158 of what would be a ~ample liquid 15~ in container 102 concave, it will be clear to tho~e qkilled in this art that a preci~ely predetermined volume or "lens" of an appropriate i~olation liquid as indicated at 160 in FIG. 13 may be disposed on the liquid 156 in container 102 and maintained centrally thereoE by the concave meni~cus 158, to ~ignificant advantaye with regard to .the effective minimization o qample liquid carryover a~
heretofore described in ~ome detail with regard to isolatlon 1 iquid len8 84 of FIG. 9.
For u~e o~ the container a~sembly 100 as a micro~ample cup, it will be understood by those skilled in thi~ art that the volume o~ containe~ 102 would be quite ~mall, ~or example 200 microl.iter~, while the inner diameter o ~he container 102 at the upper edge or lip 132 thereo~
would, eOr example, t~e a~ small a~ 0. 25 inches. Urlder the~e circlJIn3tances~ i~ wlll be clear tha~ direc~ eilllng o~ ~he corlt~ r 1~2 in ~he manner dlsclosed Eoe the ~llling o~ the miar4~ample cUp o~ United 5ta~e~ Pa~ent 4,758,409 can .. :

.
. . . :

. ~ - ~ ,: . . -sornetimes prove di~ficultr even through u~e of an appropriately ~mall pipette, due o~ course to the very small inner container diameter in que4tion. In addition, the tendency of microbubble~ to form and be contained in the very ~mall ~ample liquid volumes under discu~ion, especially upon the handling and dispen~ing thereo~ by pipette into an extremely small container, can al90 prove problematical; it being clear to tho~e skilled in thi~ art that the pre~ence of such microbubble~ in the ~ample li~uid contained in a micro~ample cup of the nature di~clo~ed in ~nited States Patent 4,758,409 can adversely impact upon the overall accuracy o~ the ~a~ple liquid analysi~ re~ult~ by lessening the actual volume of sample liquid aspirated from the microsample cup by the probe means for supply to the ~ample liquid analy~i~ sy~tem, and/or by interfering with the essentially central placement, and thu~ a~pirated volume, of an i~olation liquid len~ a~ may be emplaced thereon as described.
- Under the above circumstance~, and for use of the container assembly 100 of my invention as a micro~ample cup, it will be clear that configuration of the ~ame to provide for a ~ub~tantlally larger accessible area of the liquid chamber 128 vis-a-vis the acces~ible area of the container 102 will render the "~illing" of that llquid chamber, as by pipette, much more readily and conveniently accomplishable than direct "filling" of the containar 102; while the problem of microbubble content in the sample liquid 156 in container 102 is rendered non-existent.
Representative materials for use in the Eormation of the container of my invention for operation as described with e3flentially aqUeous liquids, for example human blood ~e~a ~alnple li~uid~, ar~ gla~ illed pla~l~ica ~UCh a~
pol~rvinylchloride or polyqkhylene, with which ~uch llquids will ~o~m ~ contac~ angle o~ le~ than 90 to readily "wet"
the aame aa re~uired ~or capillary action. ~he advantag~s :
: : ' ., ' ~' ' ,. ~ ' , -~5t7~ ~

o~ these glass-~illed plastics are ready availability, celdtively low cost, general chemical inertness, and ~uitable qtrength characteri~tics. In addition, the same are readily injection moldable, which i8 a preferred method for the fabrication of the container of my invention.
Possible alteenative~ to glass-~illed plastics as described for use in the ormation of the container of my lnvention for operation wi~h es~ential1y aqueous liquid3 are plastios, again for example polyvinylchloride, to which an appropriate surfactant, for example ethlylene oxide, has been added, or which have been pla~ma treated in the presence, for example, of oxygen to, in either in~tance, raise the surface energy of the pla~tic in question to an extent ~ufficient to in~ure the formation therewith ~y essentially aqueous liquids of a contact angle of le~s than 9o a3 required for capillary action to occur. A non-plactic material -which i~
particularly ~uitable for use in the ~orma~ion of the container of my invention for operation as described with essentially aqueous liquid~ i4 glaa9 which is readily "wettable" by those liquids.
For use o~ the container of my invention a9 representatively di~clo~ed with sample liquids in an automated sample liquid analysi~ sy~tem, whereln the container i9 of course readily and economically disposable after but a ~ingle u~e, the container i9 preferably fabricated a~ an integral unit; butr fo~ other and dieferent application~ of the con~ainer it i9 not beyond ~he ~cope Oe the apparatu~ and method of my inventlon that the ribs be fabricated ~eparately from thé container member~) and simply emplaced thereon, or affixed thereto in any appropriate manner, prior to utilization of the container.
In accordance w.ith the teachings o~ the apparatu~
~nd m~hod o~ my invention~ it wlll b~ immqdiately clear to ~h~a skilled ~n ~hi~ a~t tha~ th~ level to whi~h th~ liquid ln the conta1ner is adju~ted --a~ determined o~ coUr~e by ' .. ~ . . ~ ~ ,.
. .

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the level at which the sharp-cornered rib(s)-container sur~ace juncture~, and thus the provided capillary pathway~
for liquid flow out of the container, commence on the interior side wall of the container-- may as a practical matter be freely chosen in the fabrication of the container and ribs to range from a level immediately below the ull capacity level of the container at the relevant container lip, to a level immediately above ~he container bottom.
Thiq advantageou~ly provideq wide latitude in the choice o~
tnat level in accordance with the relevant requirements of the particular application(s) to which the container i~ to be put, all in full accordance with another stated object of my invention; and, in all instance~ as representatively disclosed herein wherein ~hat level is measureably below full container capacity, provides the additionally significant advantage, again in full accordance with still another stated object of my invention, o~ inhibiting spillage and attendant reduction in that level upon ~ignificant mechanical di~turbance o the container, for example by incautiou~ containec handling, after that level ha~ been as~umed by the contained liquid.
Since the liquid ~low rate(s) both out of and into the contalner in instance~ wherein the latter i9 relevant in all application~ o my invention will depend in large measure upon the num~er or ribs, and thu9 o~ capillary pathways provided, the llquid "head" in question which ~rive~ that liquid flow in each instance, and the respective lengths of the capillary pathways, it will be immediately clear to those skilled in thi~ ar~ that each of those pa~ameter~ may be readily varied from those as representatively disclosed herein. Thus, for example, the con tainer lQ ~E FIGS. I ~hrough 6 could inalude only one rib, o~ could alt~natively include mo~e than two oE the sam~; while wh~t~vQr numbe~ Oe ~ib~ a~e p~ovidec3 need not extend completely to th~ aontalner bottom 26. Too, and ;;, . , ~
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although the liquid flow rate( 9) will vary in accordance with those parameters speci~ied, it may be understood that the capillary liquld flow, which commences immediately upon relevant surface wetting as de~cribed, is in reality quite rapid, thu~ providing for a repre~entative total operational time for the apparatu~ and method of my invention of under 5 seconds once "filling" of the container or liquid chamber, a~ the case may be, is completed.
Although representatively disclosed herein as applied to the containment ot sample liquids for use in automated sample liquid analy~i~ systems, it is clear that the apparatu~ and method of my invention are by no means limited to use with ~ample liquids, or to u3e in conjunction with liquid analysis aystem~.
Variou9 changes may of course be made in the apparatus and method of my invention a~ disclosed herein without departing from the spirit and scope of that invention as defined in the append-d claims.

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Claims

1. In a liquid container, the improvements comprising, self-levelling means operatively associated with said container, said self-levelling means comprising means operable in response to contact by liquid therewith within the container for causing the liquid to assume a predetermined level therein.

2. In a liquid container as in claim 1, the improvements further comprising, said self-levelling means comprising, means for flowing liquid out of said container.

3. In a liquid container as in claim 1, the improvements further comprising said self-levelling means comprising, means for establishing said predetermined liquid level below the full liquid level of said container.

4. In a liquid container as in claim 1, the improvements further comprising, said self-levelling means comprising means for forming a concave meniscus on the liquid in the container.

5. In a liquid container as in claim 1, the improvements further comprising, said self-levelling means comprising, means for forming a capillary pathways for liquid flow out of laid container.

6. In a liquid container as in claim 1, the improvements further comprising, said self-levelling means being immovable relative to said container.

7. In a liquid container as in claim 1, the improvements further comprising, said self-levelling means being integral with said container.

8. In a liquid container as in claim 2, the improvements further comprising, means operatively associated with self-levelling means for collecting liquid flowed out of said container by said self-levelling means.

9. In a liquid container as in claim 4, the improvements further comprising, means operatively associated with said containerr for disposing a predetermined volume of an immiscible isolation liquid on said concave liquid meniscus for retention thereon generally centrally of said concave liquid meniscus.

10. In a liquid container as in claim 5, the improvement further comprising, said capillary pathway for liquid flow out of said container extending contiguously from a level within said container essentially coincident with said predetermined means liquid level to a level outside of said container which is below said predetermined liquid level.

11. In a liquid container as in claim 5, the improvements further comprising, said means forming a capillary pathway for liquid flow out of said container comprising means for forming a sharp-cornered surface juncture with the surface of said container.

12. In a liquid container as in claim 5, the improvements further comprising, said means for forming a capillary pathway for liquid flow out of said container comprising means for forming a plurality of separate and distinct of said capillary pathways.

13. In a liquid container as in claim 5, the improvements further comprising, said container being formed of a material with which the liquid will form a contact angle of less than 90° .

14. In a liquid container as in claim 5 wherein the liquid is essentially aqueous, the improvements further comprising, said container being formed of a glass-filled plastic material.

15. In a liquid container as in claim 5 wherein the liquid is essentially aqueous, the improvements further comprising, said container being formed of a plastic material to which a surfactant has been added to raise the surface energy thereof.

16. In a liquid container as in claim 5 wherein the liquid is essentially aqueous, the improvements further comprising, said container being formed of a plastic material which has been plasma treated to raise the surface energy thereof.

17. In a liquid container as in claim 5 wherein the liquid is essentially aqueous, the improvements further comprising, said container being formed of glass.

18. In a liquid container and a liquid supply chamber out of direct liquid flow communication therewith, the improvements comprising, bubble-free liquid introduction means operatively associated with said liquid container and said liquid supply chamber, said bubble-free liquid introduction means comprising means operable in response to contact therewith by liquid in the liquid supply chamber for flowing bubble-free liquid, only, from said liquid supply chamber into said liquid container.

19. In a liquid container and a liquid supply chamber as in claim 18, the improvements further comprising, said bubble-free liquid introduction means comprising means for forming a capillary pathway for bubble-free liquid flow from said liquid supply chamber into said liquid container.

20. In a liquid container and a liquid supply chamber as in claim 18, the improvements further comprising, said bubble-free liquid introduction means being immovable relative to said liquid container and said liquid supply chamber.

21. In a liquid container and a liquid supply chamber as in claim 18, the improvements further comprising, said bubble-free liquid introduction means being integral with said liquid container and said liquid supply chamber.

22. In a liquid container and a liquid supply chamber as in claim 19, the improvement further comprising, said capillary pathway for bubble-free liquid flow from said liquid supply chamber into said liquid container extending contiguously from a level in said liquid supply chamber to a lower level in said liquid container.

23. In a liquid container and a liquid supply chamber as in claim 19, the improvements further comprising, said means for forming a capillary pathway for bubble-free liquid flow from said liquid chamber into said liquid container comprising means for forming sharp-cornered surface junctures with the respective surfaces of said liquid chamber and said liquid container.

24. In a liquid container and a liquid supply chamber as in claim 19, the improvements further comprising, said container and said supply chamber being formed of a material with which the liquid will form a contact angle of less than 90°.

25. In a liquid container and a liquid supply chamber out of direct liquid flow communication therewith, the improvements comprising, bubble-free liquid introduction means operatively associated with said liquid container and said liquid supply chamber, said bubble-free liquid introduction means comprising means operable in response to contact therewith by liquid in said liquid supply chamber for flowing bubble-free liquid, only, from said liquid supply chamber into said liquid container, and self-levelling means operatively associated with said liquid container, said self-levelling means comprising means operable in response to contact by said bubble-free liquid therewith in said liquid container for causing said bubble-free liquid to assume a predetermined level in said container.

26. In a liquid container and a liquid supply chamber as in claim 25, the improvements further comprising, said self-levelling means comprising means for forming a concave meniscus on the liquid in the in the container.

27. In a liquid container and a liquid supply chamber as in claim 25, the improvements further comprising, said bubble-free liquid introduction means and said self-levelling means respectively comprising means for forming a capillary pathway for liquid flow from said liquid supply chamber into said liquid container, and means for forming a capillary pathway for liquid flow out of said container.

28. In a liquid container and a liquid supply chamber as in claim 26, the improvements further comprising, means operatively associated with said container for disposing a predetermined volume of an immiscible isolation liquid on said concave liquid meniscus for retention thereon generally centrally of said concave liquid meniscus.

29. In a liquid container and a liquid supply chamber as in claim 27, the improvements further comprising, said capillary pathway forming means respectively comprising means for forming a sharp-cornered surface juncture with the surface of said liquid chamber and said liquid container, and means separate and distinct therefrom for forming a sharp-cornered surface juncture with said liquid container.

30. In a method for the containment of a liquid in a container, the improvements comprising, the steps of, flowing a liquid into a container to contact self-levelling means operatively associated with said container, and causing said liquid to assume a predetermined level within said container in response to contact thereby with said self-levelling mean.

31. In a method as in claim 30, the improvements further comprising, the step of causing said liquid to assume a predetermined level within said container comprising the flowing of liquid out of said container.

32. In a method as in claim 30, the improvements further comprising, said predetermined level being below the full liquid level of said container.

33. In a method as in claim 30, the improvements further comprising, the step of forming a concave meniscus on said liquid.

34. In a method as in claim 31, the improvements further comprising, the step of, collecting the liquid flowed out of said container.

35. In a method as in claim 31, the improvements further comprising, the step of flowing liquid out of said container comprising flowing the liquid by capillary action.

36. In a method as in claim 31, the improvements further comprising, the step of flowing liquid out of said container comprising, flowing the liquid to a level outside of said container which is below said predetermined liquid level.

37. In a method as in claim 33, the improvements further comprising, the step of, disposing a predetermined volume of an immiscible liquid on said concave liquid meniscus for retention thereon centrally of said concave liquid meniscus.

38. In a method as in claim 35, the improvements further comprising, the step of flowing liquid by capillary action comprising providing a capillary pathway which extends contiguously from a level within said container essentially coincident with said predetermined liquid level to a level outside of said container which is below said predetermined liquid level, and flowing liquid along the thusly provided capillary pathway.

39. In a method as in claim 35, the improvements further comprising, the provision of said capillary pathway comprising forming sharp-cornered surface junctures between the surfaces of said self-levelling means and said container.

40. In a method for the introduction of liquid from a liquid supply chamber into a liquid container which is out of direct liquid flow communication therewith, the improvements comprising, the steps of, flowing a liquid into said liquid supply chamber to contact bubble-free liquid introduction means which are operatively associated with said liquid supply chamber and said liquid container, and causing bubble-free liquid, only, to flow from said liquid supply chamber into said liquid container in response to liquid contact with said bubble-free liquid introduction means in said liquid supply chamber.

41. In a method as in claim 40, the improvements further comprising, the step of flowing bubble-free liquid, only, from said liquid supply chamber to said liquid container comprising flow the same by capillary action.

42. In a method as in claim 40, the improvement further comprising, the step of flowing said liquid from said liquid supply chamber into said liquid container comprising flowing said liquid from a level in said liquid supply chamber to a level in said liquid container which is lower than said liquid supply chamber level.

43. In a method as in claim 41, the improvements further comprising, the step of flowing said liquid by capillary action comprising providing a capillary pathway which extends contiguously from a level in said liquid supply chamber to a level in said liquid container which is lower than said liquid supply chamber level, and flowing liquid along the thusly provided capillary pathway.

44. In a method as in claim 43, the improvements further comprising, the step of providing said capillary pathway comprising forming sharp-cornered surface junctures between the surfaces of said bubble-free liquid introduction means, and the surfaces of said liquid supply chamber and said liquid container, respectively.

45. In a method for the introduction of a liquid from a liquid supply chamber to a liquid container which is out of communication therewith, and the containment of the liquid in said liquid container, the improvements comprising, the steps of, flowing a liquid into said liquid supply chamber to contact bubble-free liquid introduction means which are operatively associated with said liquid supply chamber and said liquid container, causing bubble-free liquid, only, to flow from said liquid supply chamber into said liquid container in response to liquid contact with said bubble-free liquid introduction means in said liquid supply chamber, contacting self-levelling means which are operatively associated with said liquid container by the thusly flowed liquid within said liquid container, and causing said liquid to assume a predetermined level within said liquid container in response to contact thereby with said self-levelling means.

46. In a method as in claim 45, the improvements further comprising, the step of causing said liquid to assume a predetermined level within said container comprising the flowing of liquid out of said liquid container.

47. In a method as in claim 45, the improvements further comprising, the steps of forming a concave meniscus on said liquid in said liquid container.

48. In a method as in claim 46, the improvements further comprising, the steps of flowing bubble-free liquid, only, from said liquid supply chamber into said liquid container, and of flowing liquid out of said container, respectively comprising flowing the liquid by capillary action.

49. In a method as in claim 46, the improvements further comprising, the step of, collecting the liquid which is flowed out of said liquid container.

50. In a method as in claim 47, the improvements further comprising, the steps of, disposing a predetermined volume of an immiscible isolation liquid on said concave liquid meniscus for retention thereon centrally of said concave liquid meniscus.

51. In a method as in claim 48, the improvements further comprising, the step of flowing a bubble-free liquid, only, from said liquid supply chamber into said liquid container by capillary action comprising providing a capillary pathway which extends contiguously from a level in said liquid supply chamber to a level in said liquid container which is lower than said liquid supply chamber level, and flowing bubble-free liquid along the thusly provided capillary pathway, and the step of flowing liquid out of said liquid container comprising providing a capillary pathway which extends contiguously from essentially said predetermined liquid level in said liquid container to a level outside of said container which is below said predetermined liquid level, and flowing said liquid along that last-mentioned capillary pathway.

52. In a method as in claim 51, the improvements further comprising, the step of providing said capillary pathway which extends from said liquid supply chamber into said liquid container comprising forming sharp-cornered surface junctures between the surface of said bubble-free liquid introduction means, and the respective surfaces of said liquid supply chamber and said liquid container, and the step of providing said capillary pathway which extends from within said liquid container to the outside of the same comprising forming sharp-cornered surface junctures between the surface of said self-levelling means and the surface of said liquid container.

53. In a liquid container, the improvements comprising, means operatively associated with said container and operable in response to contact by liquid therewith within the container for causing the liquid to form a concave meniscus within the container, said meniscus formation means comprising means for forming a capillary pathway for liquid flow thereinto by capillary action.

54. In a liquid container as in claim 53, the improvements further comprising, said means for forming a capillary pathway comprising means for forming a sharp-cornered surface juncture with the surface of said container.

55. In a liquid container as in claim 53, the improvements further comprising, said means for forming a capillary pathway comprising means for forming a plurality of separate and distinct of said capillary pathways.

56. In a liquid container as in claim 53, the improvements further comprising, means operatively associated with said container for disposing a predetermined volume of an immiscible isolation liquid on said concave meniscus for retention thereon generally centrally of said concave liquid meniscus.

57. In a method for the containment of a liquid in a container, the improvements comprising, the steps of, flowing a liquid into a container to contact a capillary pathway therewithin, and flowing liquid into said capillary pathway by capillary action to cause the liquid to form a concave meniscus within the container.

58. In a method as in claim 57, the improvements further comprising, the steps of, concomitantly flowing liquid into a plurality of said capillary pathways to form said concave liquid meniscus.

59. In a method in claim 57, the improvements further comprising, the steps of, disposing a predetermined volume of an immiscible isolation liquid on said concave liquid meniscus for support thereon generally centrally of said concave liquid meniscus.