US2371509A - Liquid gauge tube - Google Patents

Description

March 13, 1945. N. DoBRzYNsKl LIQUID GAUGE TUBE Filed May '19, 1942 www5.

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Patented Mar. 13,-1945 52,371,509/ 'LiQUID GAUGE"runt:I41 NusynDobrzynski, Haderah,ffPalestine,.if ApplicationMayia, 1942, lserial No, nafiisi f In Palestine October 9, j194 1' This invention relates'to yvolumetric pipettes generally, such as-used-in chemistry'or bacteriology, and inter-alia-t@ mixing pipettes, that is, pipettes into which two liquids are sucked in one afterthe other in order to be inixednthe pipette in the desired exact `proportion. yThis invention is especially useful in itsapplicationto the dilution `of -blood inl connection with blood count. i

The general purpose `of pipettes is to allow of as exactimeasuringsiof liquids asY possible. With the .common type of pipettes, the liquid is-usual1y sucked in with the'` mouth and adjusting .of` its level ingthepipette is done indifferent ways;- As I a: rule thetop end of thepipette is-.closed by the` nger, and by gradually lifting the finger the liquid isfallowed to ow out until its level reaches exactlyv the mark. With capillary ypipettes, the adjustment of the level isA obtainedby' slightly blowing airinto the pipette and; bygwipingI its 20l outer end so-as togsuck liquid out .ofv the-latter.v These methods are notexpeditiousand are subject to individual` abilities. Therefore, the measurings are rliable tobe inaccurate; After into closing pcjsitin; ca therefrom without thereby sucking liquid out of agfainbeen brought lobturator whenthelatte asily be Washed -off theint'ake enq'cfthepiptte. l f

As already inentiondl above; l the Vinvention is particularly useful-in its application to Imixing pipettesfffor diluting blood for""blood"'count.

', Diiferent dilutingratios x'and =diluting liquids are required for counting erythrocytes -vand leucocytes wherefore twodiiferent Vpip'ettes are used.

Hitherto, v one diluti-ngfoperation hasf'flrst yto 'be vcompleti-idfa1"id` ,o nly then 'canthe second one be started wljlji'ch I 'nals itA necessary in'niany cases to make a'v fresh? prick in order to obtain a further sample "of blood'vifron' the patient.-"-;

According to this invention; f two -""mixing` pipettes serving respectively forierythrocyteand "'leucocyte 'countingfare mounted en a common support and connected' tof a 'cornm'oi rubber bulb so that a reduced or-'elevated pressure can b ecreated'iin bothl offthenr at' the same-time,

separate controlinlean's@ The two diluting loperations can ,befperfornied' at' the 'same time from the levelof the liquid-has been; adjusted, there, ,2 5f,two 'samplesfofbloodf takenrorn the patient remains an excess drop .oiliquid` atn the outflow*l end of the pipette and the necessary removal of this drop draws psome liquid out lofthe pipette which makes themeasuring faulty. Besides,-'the Operation ofl sucking in the iiquidybythe mcuthaof hasv obvious drawbacksA from a hygienic point of View. l 1 c Y v Itis also knownl tofconnect compressiblerubq An; executiony for-m "of an is blood 'diiutmgfdevicev Y Fig'. a corresponding vvside elevationj'with some partsbeing omitted;

'ber .bulbs t0 the top-of' pipettes whichallow. of

sucking the liquidfinto and pressingy it out ofthe; vpipette by creating -1 respectively reducedand elevated pressure'within vthe pipette. Known ar-A rangements ofthis kind, while being satisfactory from a hygienic poin'tof view, do not add to the accuracy of the measuring.

crease the accuracy' of' means of pipettes.A 'i f The inventionrconsists essentially in the pro# vision ona pipette of an obturator foriclosing its-g ,Figl l3 a rear lview, partlylbrokenf away-Jt f' A.In the'execution formfiiiustrated, a pipette 1 l leucocytecquntihg; with' mixing-bulbs 1', z f e-f spectively; are mounted" in parallel on a'plate3 for'erythrocyte'oounting anda pipette 2- for 40i The mam object of this invention is -'wf111,-""

measuringsl effected .by

"They are connectedfthroughrubber tubesv if,v 5'

tic-.aff a nxedtc plate vs-"bymneairisorf-Ming 1. The third branch bf T6 bears a compressible hollow rubber bulb 18.*-, Ahole 9-is"p'rovidedin T -6 'and this isnormallyfclosedfby ashutter 'I0 pressed intake end. andof mechanical means for press'- ing `the obturatorAag-ainst said intakeend and gradually removing it therefrom in ordertocom trol` the rate of flow of' the liquid enteringV or4 leaving the pipette by the action of saidv reduced-h or elevated pressure from zero up' to 'a full free flow. By.regulatingthe rate of flow .to a small value, a highly exact adjustment 'ofthe liquid level in the pipette .to the desired mark `can be obtained. Any excess of liquid left ony thea..4

thereagainst'i by" xn'eans`V of 'a' fle'X-ion jspring'- II which isjnxe'd ytcijth'e pack of piatte a: vA further v flexionvk spring 512 is-fixed` to plate 3l in such position that itcan' bev pressed'against tube. 5 whereillustrated'fbyway of"examplefin'the-accoinrod there extends a horizontal fork over the.

band is thus drawn up against the end of the pipette by springs 20. If now the obturator is lowered and rod I5 is turned by about 180 so as to bring the obturator away from the pipette, the

rod I5 is urged upwardly and .follows the traction until an abutment 2| iixed to it applies. itselfjtov ,V the clip I6. The abutment 2l is in the form of u n two small arms projecting laterally from the rod.` A lever 22 is articulated to yplate 3 so as to rest on knob II. This lever has a knob 23 and serves for lowering l-veryslowly the obturator from the end of the pipette. Now,-this should sometimes be carried out with the utmost care and over a veryv small way only, especially `in the case of very tine capillary Apipettes. j This object can -be attained by providing a further lever 24, equally articulated to plate 3 above the lever 22 and adopted toA rest on a stop 25 iixed on plate 3.y

This lever has ,at its free end a threaded sleeve 2B in which a screw 2llisV inserted, and by screw ing this downwardly while levery 24 is at the same time pressed against stop 25, lever 22 is slowly pressed down at avery slight rate of motion, and the rubber band `is accordinglyA very gradually removed-from 'the pipette.` A similar arrangement may be provided with the other pipette as Avwell, but this has been omitted inthe drawing Yfor the sake of simplicity. l

. It is evident that by :very slightly lowering the .rubber band,onlyy avery narrow slit is 'created between the .end of 'the pipette and the rubber band through which slit the liquid can only very slowly enter or leave the pipette, as the case may be, which allows of avery exact andconvenient adjustmentjof its level ,in .the pipette or of the amount withdrawn.v On the other hand, if .a large amount of liquid is rapidly to be sucked in or pressed out, the obturator is fully lowered and possibly turned away. l i. l

The apparatus described by way of example is operated in the following way: l

Screw I3 A`is tightened so as` to compress the tube 5 almost entirely. One obturatoris lowered -and turned vaway from the ,end` of its pipette, and

this end vis dipped ina drop of blood, such as obtained by aprickon a iinger tip, whereaiter screw I3 is untightened so much as to cause some blood to be sucked intothat pipette and to rise therein a little above the mark provided for deter mining the exact amountrof blood to be taken. The obturatoristhen put back into closing position. The same procedure is repeated with the second pipette for lwhich the supply of blood obtained by that one prick is still sufcient. Now.

Y both pipettes beingv closed and each of them containing an excessy of -blood screw I3 is again tightened by oneturn or oneturn and a ha1f,w

whereby the pressure in bothpipettes is raised. INOW, one of the levers 22 is carefully pressed iupon, which creates a narrow slit between the pipetteV and the rubber bandthrough which a quantity of blood is expelled until the level of the blood in the pipette reaches exactly the mark,

and at this moment lever 22 is released. The same is then done with the second pipette.

Instead of sucking the blood from the prick, as described above, some blood can be puty on both obturators at a time directly from the i'lnger tip (which is particularly indicated where no substantial drops of blood into which the pipettes can be dipped form on the puncture) while screw i3 remains tightened, then the 'obturators are put back into closing positions so as to let the ends of the pipettes `dip into the blood drops.

"LWhen screw I3 is now untightened, the pressure lowers in both pipettes but nothing happens until by again slightly lowering the obturators the blood'can be sucked in fromthe obturator. This is done with one pipette after the other, and by careful work i-t is possible to stop the inilow at the very moment when the blood has risen to the mark.

With both methods, any excess of blood to be found on the obturators is then washed off. Spring il is now pressed upon from the back of the apparatus so as to uncover hole 9, thebulb 8 is compressed and the spring and bulb are then released one after the other so that the bulb is now evacuated. Finally, the ends of the pipettes are dipped into the diluting liquids, one obturator after vthe other is again carefully lowered by means of the corresponding lever ahd the respective liquid is sucked into each pipette' up to the provided mark. This is best done with both pipettes simultaneously by means of a vessel divided into two compartments'each of them containing one of the diluting liquids, so that both pipettes are dipped in their corresponding liquids Vat the same time.

yfrom each pipette and put inv a counting chamber. Bulb 8 can be removed from'T 6 for cleansing and drying the pipettes.

The invention can be applied also to other liquid gauge tubes, such as burettes.

I claim:

l. Device for the accurate. measuring of liquids, comprising in combination, a liquid gauge tube, a shift rod adapted to move parallel to the axis of said tube exteriorly of said tube and to be turned about its own axis, an obturator including a piece of resilient material mounted on the bottom end of said rod, at least one spring serving tol press said obturator against the bottom end of said tube for closing its opening, and a lever adapted to press on said rod for shifting the rod against the action of said spring for the purpose of controlling the rate of flow of liquid through said end of the tube.

2. Device for the accurate measuring of liquids, comprising in combination, a liquid gauge tube. an attached device connected to the upper end of said tube and adapted to alternately create elevated, atmospheric and reduced pressure in saidtube, an obturaton'including a piece of resilient material disposed beneath the bottom end of said tube, and mechanical means serving to press said obturator against said bottom end for closing its opening, .and allowing said obturator to be moved graduallytowards and away from said end for controlling the rate of flow of ,liquid therethrough.

3. Device for the accurate measuring of liquids, comprising in combination a liquid gauge tube, an elastic bulb and connecting lmeans including an elastic tube connecting said bulb to the upper end of said gauge tube, mechanical means serving to compress said elastic tube to anyy desired degree, an obturator including a piece of resilient material disposed beneath the bottom end of said gauge tube, and mechanical means serving to press saidobturator against the bottom end of the gauge tube for closing its opening, and allowing it toibe moved gradually towards and away from said end for controlling the rate of flow of liquid therethrough.

4. Device for the accurate measuring of liquids according to claim 3, having an air communcation port in the means connecting the bulb to the upper end of the gauge tube, closing means in conjunction with said air communication port, and a spring serving to press said closing means on said air communication port. p

i Device for the accurate measuring of liquids, comprising in combination, a liquid gauge tube, a shift rod adapted to move parallel tothe axis of said tube and to be turned about its own axis, an obturator including a piece of resilient material mounted on the bottom end of said rod, at least one spring tending to press said `obturator on the bottom end of said gauge tube for closing its opening, a lever serving to press on said rod for shifting the rod against the action of said spring to control the rate of iiow of liquid through said end of the tube, a support on which said lever is mounted and to which said spring is connected, a sleeve with an inner thread mounted on said support, an adjusting screw inserted in said sleeve and adapted to be applied against said lever for pressing it on the said rod,

an elastic bulb, and connecting means including an elastic tube connecting said bulb to the upper end of said gauge tube, an air communication port in said connecting means, closing means associated in conjunction with said air communi-` cation port, and a spring tending to press said closing means on said air communication porta` 6. Device according to clairn 5, comprisingan abutment provided on the support above said lever, a further lever swingingly mounted on said support and adapted to be applied against said abutment, the said threaded sleeve being carried blood count, comprising in combination, two mix` ing pipettes arranged in parallel, a common support carrying said pipettes, two obturators each,

including a piece of resilient material individually disposed beneath the bottom end of each pipette, mechanical means* serving to separaly press each obturator against said ends of the pipettes for closing their openings and allowing the obturators separately to be `moved gradually towards and away from said ends for controlling the rate of flow of liquid therethrough, and a common attached device connected to theupper ends of said pipettes and adapted to alternately create elevated, atmospheric and reduced pressure in said pipettes.

' 8. Device for measuring and diluting blood for blood count, comprising in combination, two mixing pipettes arranged in parallel, a common support carrying said pipettes, two shift rods, one in conjunction with each pipette, said rods being guided on said support` parallel to said pipettes and adapted eaah-to be turned about its own axis, obturators comprising each a piece of a resilient material, each mounted on the bottom end of one rod, springs adaptedto press each obturator separately against the bottom end of` its pipette, vtwo swinging levers in conjunction with said rods, said levers being swingingly mounted on said support and adapted separately to press on the top ends of said rods and to shift the rods against the action of said springs, and allowing separately to move said obturators towards and away from said ends of the pipettes for controlling the rate of iiow of liquid therethrough, Ia T with three branches mounted on said support, elastic tubes connecting the top ends of said pipettes respectively to two branches of said T, clamping means adapted to compress l one of said elastic tubes to any desired degree,

an elastic bulb connected to the third branch of said T, an' air communication port lin said T, a

shutter adapted to close said air communication port, and a spring adapted to press said shutter

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