Note: Descriptions are shown in the official language in which they were submitted.
Z~ :iit7~3X
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
.
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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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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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.
l ;
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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11
_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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12
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 ~
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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
.
. . : . . .
16
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
17
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
18
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
19
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 ~ ~
21
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~
23
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~
26
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
'' ~ :
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X~ 78Z
28
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~
29
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
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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
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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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