US2001581A - Gas absorption pipette - Google Patents

Description

May 14, 1935.

' M. P. MATuszAK l GAS ABSORPTION PIPETTE Filed oct. 233, 1935 INA'ENTOR f da@ JM WH'NESSS Patented May 14, 1935 PAT,

G As ABsonPrIoN PIPETTE A Maryan P. Matuszak, Pittsburgh, Pa., assvg'nor to Fisher Scientiiicl Company, Pittsburgh, Pa., a corporation of Pennsylvania Application October 23 l 9 Claims. This invention relates to pipettes used in gas analysis, and moreparticularly to bubbling gas` absorption pipettes ofthe type having automatic control valves 'and which are usedin gas'analysis '5 vapparatus 'ofthe well known Orsat type.

lHeretofore such pipettes commonly have been provided with valvesmade hollow so that they might float in the liquid absorbent, and it has also been necessary'to provide special means for 10 guiding VAthe float valve so that it would seat itself properly.` This hasv usually takenthe form ofone or more projections from either the upper or the' lower side of thelloat valve. In addition, because of the Iloating character of the valve, one or more projections, or baies, from the inside upper wall of the valve chamber, have been necessary to further keep the valve in place or to prevent-its entering and closing off `the inlet to the valve chamber. A

Furthermore,V the v'effective or operative portions of 'the float valves heretofore used in pipettes of ythis type have been of an essentially conical `shape such asto present -a rconsiderable region of contact when seatedron the valve seat, whereby itnot infrequentlyhappened, despite claims to the contrary,` that the valve froze or stuck fast in its seat. VThis undesirable veffect has been aggravated by having the valve seat also ofA an essentially conical or a cup-shaped construction, which has offered some resistance to the free movement of the valve. Consequently, such prior pipettes have suffered from various disadvantages, chief among which has been the fragility due to the structural features just mentioned. Their fragility has been enhanced also .by the factthat the bubbling tube which conducts the gas into the absorbent has been connected to the valve chamber at a point located above the valve seat, and passedthence as an exterior tube, paralleling the Valve chamber,to'a point klocated below the valve seat, at whichlatter point it entered the absorption part of the pipette. This construction has not only made the pipette 'very' fragile and easily broken` but has detracted from the appearance of the pipette, because of its unsymmetrical design, and has decreased the effective or operative height of the pipette, because of the space requiredA by Ythe exteriorly located valve chamber and gas conducting tube and their common juncture. r Y Major objects of this invention are to provide improved gas absorption pipettes, which are sim'- ple, sturdier than those available heretofore, and which eliminate or minimize the disadvantages of fthe pipettes known inthe art.

, 1933, serial No. 694,763

The invention may be described in connection with the accompanying drawing, Which is a ver-I tical or longitudinal section through thecenter of the preferred embodiment of the invention.

The pipette comprises a pair of containers connected at their lower ends to act as absorption and expansion elements, the absorption ele-ment being provided at its .upper end with a vgaszinlet connectiom.preferably tubular. These vcontain'- ers maybe separate tubular Amembers connected at their bottoms by an integralttube,14 as in the conventional forms commonly used with Orsat apparatus, but itis preferred to. arrangethem within one another in a manner Vdescribed hereinafter.v

In accordance withv the invention the absorption container is provided adjacent Vits upperend with means, such as a partition wall integralwith the container, dividing the container interiorly into a valve chamber and an absorption charnber'. Theivalve chamber wall is providedfwith a valve opening adapted to act as a valve seat for a valve member which is guided within vthevalve chamber towardand from thefseatV thus provided. Although various forms of Valve meme' ber may be used, itis preferred rto use spherical valves, and most advantageously truly spherical glass balls, forreasons presently to be pointed out. Most advantageously the bubbling,.orfgas` conducting, tube commonly embodied insuch a pipette lies Wholly within thepipette, extending, for example, from the valve chamber downwardly within and to the lower portion of the absorption chamber.4

Having reference now to the drawing, the embodiment'shown comprises an absorptioncontainer l and an expansion container 2, each of generally cylindrical vcross section. The upper end of the absorption container is provided with a projection of reduced cross section,` such as the tube-like projection a, to whichfthere isfcon nected a gas inlet connection, such as a capillary tube VThe gas inlet tube may be arranged in various manners, but preferably itis aligned with projection la, as shown, to be central to the container. The container is divided into a'valve chamber 1i and an absorption .chamber 5A by a partition or valvev chamber wall 6 interiorly" of and integral with the container. The Valve wall is provided with an .opening 1 arranged below' and centrally of the-*projection la, and thus inthe form shown centrally vof gas inlet 13. The upper side of opening 'I is shaped to provide a seat vfor a valve'- rnember'a, most suitably by shapingthe wall as shown in the drawing to form a short 55 am oFFIcE i tubular extension 1a of opening 1'. Valve mem-V ber 8 advantageously is non-floating, suitably in the form Yof a -spherically true non-floating ball, e. g., of solid glass.r I p They upper partrof the valveY chamber, i. e., projectionY Ia1 in the form shown, is of such form and size and so, positioned with respect to the valve Vseat that 8 ,is retainedfor and guided in itsmovement toward iand from itsseat in `opening 1, and so that it can not 'escape laterally into the sides or bottom of the valve chamber.

Y In the preferred embodiment of the invention the lower portion of container I is* ,of cross-sectional area', which confers important advantages presently described. VExtending vdownwardly into the lower portion from the lower .epd of'wall 6 is a'tube 9 which terminates in a hollow perforated sphere I0, to provides. bubbling tube.

f Expansion chamber 2' surrounds and totally encloses the lower, `reduced section portion of the chamber, as shown in the drawing. The twoeontainers are .cormected at their lower 'ends by permutations, or notches lII formed atthe lower .end of .container I.

It willl be noted the invention provides a pipette of sim-ple and sturdy design Vsince vthe vaalvechamben valve seat,-a.nd bubbling tube are notv only integral with ntlie'absorpftioi'i vessel of the Apipettebut are `entirely within'and sur- 'rounded by it, so that nofragijle exteriortube Y orvalve chamber is present.` Features of the seat .consists of' the end of Va short'. upwardly Pro? looting tubeand. is not cup-shaped, sothat it does not offer anyA Vresistance .to the free movement of valve. it will be noted that lthe appearanceof. the isneat, because .of the general symmetry of the design, and Ythat the eective. or operativelheightof the pipette has not'heen appreciably' decreased Vby the inclusion .of the vol-,ve feature. 1

1 :inthe practice of this'invention the liquid ab.-

v has sorbent in the absorption container I is drawn up to a point above the valve chamber in a manner well known to those skilled in the The Sample of gas is then propelled into theV pipette .through .the capillary 3 at the top of the pipette.

liquid" absorbent is, thereby forced from the valve .chamber 4 througi1-thebubhling tube s and is followed'bv the. gas, ywhich, issues in the form .ofrv bubblesf-'rom the perforations in the hollow sphere ill.` The gas'cannot pass through the -of the valve seat. 1 because this opening isi vcloser! by the valve 8., 'Ihe bubblesof gasrise throughand collect above the absorbentin `(,:l'minber 5, the absorbent being correspondingliv forced; into the expansion chamberformed by container v2. A plug of liquid remains in the short Y tube whose upperxend comprises the valve seat 1.

When it is desired to discharge thel pipette ofV the residual unmbsorbed'gas, a slight decrease in pleasure is 'createdin valve chamber l, in a manner familiar to those skilled in the art, as by the ,of a leveling bulb connected to afgas Minette; nots-shown. .Y This causes the gas to rush Vthe valve seat. y

from the pipette withoutcausing the ball to rattle onvibrate or interfere in any otherV way with up through the opening of the valveseat 1, push-v ing up and` aside the ball 'valve 8 and the plug or liquid beneath it. 'Ihe ball valve, wet by the plug of liquid', sticks to the adjacent side of the upper part of the valve chamber, by virtue of the surface tensionexerted by the liquid that wets it and the region surrounding the point of contact, so that it rests .on the rim of partly ,overhangs This permits the gas to `escape the upward passage of the gas. When the gas is discharged from the pipette the liquid 'absorbent rises above the ball valve, completely surrounding ,it ,and removing the surface tension effect mentioned above, whereupon the ball valve falls back into the valve seat and the pipette is readyrfor the next passageof gas. y v

An addition feature wherein the embodiment of Ythis invention differs from and is superior to previous gas' absorption pipettes used in gas analysis apparatus of the well' known Orsalt upper and lower regions Lof the on .container I'of" the pipette.. lcontainer I is larger, advantageousla ahomo mms, and the lower portion smalierg'l advantageously about :27 in diameter, than. the Ial sorption parts of other pipettes, have untform diameters ranginsirom 32 to42 This novel arrangement! offers two adlies in the `vdiierence in the cross .of the Y l vantages. The first of .that the expanded Y upper portion permitsthe colledcionroi, the Isus that has bubbledthrough oban-bent, ,dunne the passage of the gas samplc;.-without the length of the 4eioctive orfoperstiue--column of absorbent as vmuch vas inlpipettes portion of a smaller Theseomddvantage is that the lower narrowfportionf the liquid absorbent to` owdownwardhwith .creater velocity im nineties havinejthis, partici 'greater diameter, thus appreciably ,slowing .the upward rise of the zas bubios,A Becausoof these two advantages .of contact ofthe ess 'bubbles with f the` made longer; thus increasing the emoienoy .ofl absorption,fwithout increasing the time required. forosof the sas; sample; f

According to the vomitidas ai me; patent Astai-V utes, Ihave explained the constmction and mode of operation of my invention, and have -iliustrated and described what I now'considerits best Vem'- bodiment. Howevenldesire to bereit understood that, within the scope of the appended claims, the invention may beA practiced otherwise `than as specifically illustratedand .describemf If Claim:

of containers connected at theirlo'werfends, the combination with one of saidv containers'of agas inlet tube Iconnected to the upper end ofthe con. tainer, a partitionwali provided with a psico! openings lying within the container upper end and vIdividingrthe container into an upper valve chamber anda lower absorp` tion chamber, a shorttube projecting upwardly l. In a `gas absorption pipette comprising. apair Fifi into they Valve chamber froxnone of said openings withits upper extended end concentric tosai'd valve chamber and forming` aV valve seat,a gas conducting, or bubbling,-y tube extendingudownwardly'from the otherl of. said openings into the lower part of said absorption chamber; md. a valve member disposed in said valve chamber for cooperation withsaid valve'seat. Y f" 'v 2. A gas absorption pipette Ai .pair

of containers connected at their lower ends, one of said containers having its upper end of generally conical form and having a gas inlet tube connected to the upper end thereof, a partition wall lying within the container adjacent its upper end and provided with a pair of openings, said partition wall dividing the container internally into an upper valve chamber and a lower absorption chamber, a short tube projecting upwardly into the valve chamber from one of said openings with its upper end concentric to said valve chamber and forming a valve seat, a spherically true ball valve member disposed in said valve chamber for cooperation with said seat, and a gas conducting, or bubbling, tube extending downwardly from the other ofv said openings into the lower part of said absorption chamber, said tube lying wholly within the container.

3l A gas absorption pipette comprising a pair of containers connected at their lower ends, one of said containers having its upper end of generally conical form and having a gas inlet tube connected to the upper end thereof, a partition wall lying within the container adjacent its upper end, said partition wall being provided with a pair of openings and dividing the container internally into an upper valve chamber and a lower absorption chamber, a short tube projecting upwardly into the valve chamber from one of said openings with its upper end concentric to said valve chamber and forming a valve seat, a solid glass spherically true ball valvejmember disposed in said valve chamber for cooperation with said seat, and a gas conducting, or bubbling, tube extending downwardly from the other o1' said openings into the lower part of said absorption chamber, said short tube and said bubbling tube lying wholly within said container.

4. A gas absorption pipette comprising an absorption container and an expansion container connected at their lower ends, said absorption container having a gas inlet tube connected to its upper end, a partition wall within the absorption container adjacent its upper end, said wall being provided with a pair of openings and dividing the container internally into an upper Valve chamber and a lower absorption chamber, a short tube projecting upwardly in the valve chamber from'one of said openings with its upper end concentric to said valve chamber and forming a valve seat, a gas conducting, or bubbling, tube extending downwardly from the other of said openings into the lower part of said absorption chamber, a spherically true valve member disposed in said valve chamber for cooperation with said valve seat, and said absorption container being of reduced cross sectional area along a substantial length of its lower end surrounding said absorption chamber.

5. A gas absorption pipette comprising an absorption container and an expansion containerl connected at their lower ends, said absorption container having at its upper end a tubular projection of substantially uniform diameter, a gas inlet tube connected to said tubular projection, a partition wall lying wholly Within the container adjacent its upper end and cooperating with said tubular projection to form an upper valve charnber, the lower portion of the container below said ywall forming a lower absorption chamber, said wall being provided with a pair of openings, a

short tube projecting upwardly from one of said openings with its upper end concentric to said valve chamber and forming a valve seat therein, a spherically true ball valve member disposed in said valve chamber for movement therein and cooperation with said seat, and a gas conducting, or bubbling, tube extending downwardly from the other of said openings into the lower part of said absorption chamber, said short tube and said bubbling tube lying wholly within the container.

6. A gas absorption pipette comprising an expansion container and an absorption container arranged axially within the expansion container and provided at its lower end with openingsconnecting the containers at their lower ends, said absorption container having a gas inlet tube connected to its upper end, a partition wall lying wholly within the absorption container adjacent its upper end and cooperating therewith to form a valve chamber, said partition wall being providedV with a pair of openings, the portion of the container below said wall forming a lower absorption chamber, a short tube projecting upwardly to the valve chamber from one of said openings with its upper end concentric to said valve chamber and forming a valve seat, a solid glass spherically true ball valve member disposed in said valve chamber for cooperation with said seat, a gas conducting, or bubbling, tube extending downwardly from the oher of said openings into the lower part of said absorption chamber, and said short tube and said bubbling tube lying wholly within said container.

7. A pipette according to claim 5,'the lower portion of .said absorption container being of reduced cross sectional area along a length surrounding at least about one-half the length of said bubbling tube. 1

8. A pipette according to claim 6, the lower portion of said absorption container being of reduced cross sectional area along a length surrounding at least about one-half of the length of ,Y

said bubbling tube.

9. A gas absorption pipette comprising an exforming an absorption chamber7 said wall being providedY with a pair of openings, a short tube projecting upwardly from one of said openings to said v valve chamber with its upper end concentric thereto, and forming a valve seat therein, a gas conducting or bubbling tube extending downwardly from the other of said openings into the lower part of said absorption chamber, both of said tubes lying wholly within the container, a spherically true valve member disposed in said valve chamber for movementl therein and cooperation with said valve seat, and the lower portion of the absorption chamber being of reduced cross sectionalarea along a length surrounding at least one-halfrthe length of said bubbling tube.

MARYAN P. MATUSZAK.

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