|Publication number||US2622765 A|
|Publication date||Dec 23, 1952|
|Filing date||Sep 14, 1948|
|Priority date||Sep 14, 1948|
|Publication number||US 2622765 A, US 2622765A, US-A-2622765, US2622765 A, US2622765A|
|Original Assignee||Emil Greiner Company|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (5), Referenced by (9), Classifications (7)|
|External Links: USPTO, USPTO Assignment, Espacenet|
Patented Dec. 23, 1952 "STATES OFFCE `MICROBURET OR "PIPEI Roger "Gilmon't, Brooklyn, N. Y., assigner to The Emil GreinerCnmpany, New York, 1N. Y.,.a:corporation of "New York Applicationseptember 14, 1948, 'Serial No. 49;187
Theinventionhereindisclcsed v'rela'testo burets :and pipets pf the -capillary type.
llt is known "that the diiiiculty in handling "these-devices increases with the use of capillary Itubing-since `the effect of surface Atension'becomes increasingly evident as the 'sizeof the capillary decreases, leading 'to drainage verrors vwhich vitiate 'the i'accuracy of measurement.
lGlbje'cts-of -the present invention are to effect the eliminationc'f drainage errors and to provide can extremely -accurate and sensitive microburet for Jpipet lf fsimple, -inexpensive structure which 4'can 'ibe easily `adjusted and -quickly and easily fread -as 'the adjustments are made.
'Important objects of the invention 'also are tc vpr-oviid'e a'structurefo'f the Ycharacter indicated `ul'lich will be adapted and suited to the many land varioustitration problems involved in analytical chemistry, both liquids vand gases.
Other desirable "objects rvattainedby the invention and the novel features of construction through which such objects are attained are set forth or will yappear inthe course of the following specification.
The drawing accompanying 4and forming part of the specification illustrates present practical commercial embodiments of the invention. Structure, however, may -be modied and changed as regards such illustrations, all lwithin the-true `inten-t 4and broad scope of theinvention fas hereinafter defined and claimed.
Fig. l in "the drawing is Aa `top plan view r0f foneV o'f 'the `new microburets;
Fig. 2 is a front elevation of the same;
Fig. 3 is an enlarged broken sectional detail of thevrotatable and separable connection between the fine adjusting screw and the spindle of the microgauge;
Fig. 4 is an enlarged broken sectional detail of the mercury reservoir structure and piston at the base of the capillary tube;
Fig. 5 is a plan view of a micropipet instrument with portions shown in cross section.
In Figs. l and 2 the microburet is shown as made up of a base 1 on which there is mounted a direct reading microdial gauge 8 adjusted by a line screw 9 and in turn connected to actuate a piston I0 operating in an aligned, transversely disposed mercury reservoir II at the base of a capillary tube I2. looped at the top at I3 in gooseneck formation and terminating in a downwardly directed, nne orice I4.
The gauge is suitably calibrated, as to read directly in .0001 cc. divisions and is shown mounted by screw I5 on an upstanding boss or l2 Claims. (Cl. 1222-446) iii) stud I`6 on the `basein "horizontal position 'with its spindle :I 'I exposed atone end V*to theadjusting screw and at the opposite end to thepiston'rcd lor element I0.
The 4-ne screw '9 `is 'shown 'as oi'lerating v'iin ra screw post IB y'on the ba-se 'and as 'havingfaknob -or operating crank It@ Vat `outer vend land a -^cou pling 20 'at the inner end, lthe latter v'carrying a thumb screw l2I engaging in an 'annular `'groove `212 in the gauge spindle itc provide a rotatable and separable connection 'between `.the adjusting Yscrew rand spindle.
The "gauge spindle is shown ashavingsa direct positive screw 'connection l23 with the l end 'o'f "the, piston element I-li.
The transversely disposed mercury reservoir at the flower fend of the lcapillary itube vis shown as utilized for mounting this tubing by gripping it 'between opposed screw 'plugs or 'bushings iu, '25,fengaged in lspaced studs y'or posts 226, 2:'1, rising from the base.
The closed end 28 of the reservoir for piston chamber is :shown inFigfli as setting in fa socket 129 iin the lend 4o vscrew plug 24, backe'd 'up -by ra cushioning disc 0r 'washer 30.
"The-Opposed companion screw v.plug :25 i's-esh'own .in Ei'g. 4 as having la bcre C31 itc freel-y `pass the piston ielement fand -a `socket '32 'to .accommodate the fopen 'end -of fthe reservoir chamber and the packing washer 233.
`lilljustrnent -Uf the :screw zplugs '12:1 fand 25 :clamps fthe `capillary .tube .in proper relatinn on fthe stand 10i Jvvith lthe ipacking `.washer 33 properly sealing the piston where it passes into the reservoir chamber.
The upper portion of the capillary tubing is shown as supported and held to the stand structure by a clamp 35.
By the means described the cooperating parts Of the instrument are properly aligned but removably supported on the base.
Additionally, the base may carry one or more upstanding rods or posts such as indicated at 36 for carrying test tube clamps or clamps for r stirring devices or the like which might be used in titration operations.
, Minute adjustments of the ne screw will show clearly on the direct reading micrometer gauge, and these adjustments will be mechanically transmitted to the mercury piston through the medium of the gauge spindle, the mercury operating as a liquid piston to deliver the titration liquid previously charged in the capillary tubing ahead of the mercury.
' The rod I0 forming the piston is 0f the same cylindrical dimensions throughout its active eX- tent so that equal movements of the same will create equal volume displacements and these are directly and immediately readable on the dial of the gauge.
The instrument, therefore, is both sensitive and accurate with possibilities of error practically eliminated.
The invention may be embodied in micropipet form as illustrated in Fig. 5, which shows a pipet tube 31 having a mercury chamber 38 at the end of the same receiving a cylindrical piston 39 connected at 49 with the spindle 4l of the microgauge 42.
A micrometer screw adjustment effect is obtained in this instance through the differential action of different pitched screws 43, 44, on the spindle and on a surrounding sleeve 45, respectively, these two different screw elements being engaged by corresponding pitch internal and external screw threads 46, 41, on a micrometer sleeve 48 having a finger knob or disc 49 for turning the same.
The screw sleeve 45 is slidingly mounted on the tubular guide 50 for the gauge spindle but is held against rotation thereon by a pin 5| projecting from the bushing through a slot 52 in the sleeve so that with rotation of the screw the spindle will be advanced one way or the other an amount equivalent to the difference in pitch between the two sets of screw threads 43 and 44.
While particularly designed for micro or ultramicro operations, it will be appreciated that the invention may be used for macro work as well, in all cases providing a high degree of accuracy and quick, easy readability in a simple, low cost, structural form. The invention is equally well suited to gases and liquids and in any volume. If the liquid which is to be handled reacts with mercury then the liquid alone may be used, without mercury.
What is claimed is:
1. A microburet or micropipet comprising tubing having a small discharge orice at one end and a displacement chamber of larger dimensions at the opposite end, a piston rod of uniform dimensions'mounted to operate in the end of said displacement chamber, a direct reading gage having an operating spindle, means securing said gage with one end of said operating spindle in alignment and engagement with the outer end of said piston rod and an adjustment screw in alignment and connected with the opposite end of said spindle and whereby ne adjustments of said screw will actuate the spindle of said microgage and said spindle at the same time will transmit displacement adjustments to said piston rod.
2. A microburet or micropipet comprising a base having horizontally spaced, upright supports, screw plugs mounted in horizontally opposed relation in said supports, said screw plugs having horizontally opposed sockets in the inner ends of the same, a length of tubing having its opposite ends seated in and removably held in the sockets of said screw plugs, a capillary tube in communication with and extending upwardly from the intermediate portion of said tubing, said tubing being of larger diameter than said capillary tube to constitute a reservoir for mercury or titration fluid, said capillary tube having a gooseneck at the upper end of the same terminating in a downwardly directed capillary discharge orifice, one of said screw plugs having an opening through the end of the same in line with said tubing, a piston rod of uniform dimensions extending through said opening into the tubing, packing in the seat in said plug at the end of the tubing engaged in said seat and surrounding said piston rod, a direct reading microgage having a plunger for operating the same, means supporting said microgage on said base with one end of said plunger in alignment and engagement with the outer end of said piston rod and whereby said piston rod will be actuated by said microgage plunger, and an adjustment screw mounted on the base in alignment and engagement with the other end of said microgage plunger and whereby fine adjustments of said screw imparted to the plunger of the microgage will be transmitted by the plunger to said piston rod to effect displacement of contents of said reservoir tubing in respect to the capillary tube connected therewith.
REFERENCES CITED The following references are of record in the rile of this patent:
UNITED STATES PATENTS Number Name Date 215,300 Sherman May 13, 1879 635,154 Smreker Oct. 17, 1899 2,158,774 Grubelic May 16, 1939 2,412,295 Shaier Dec. 10, 1946 2,464,714 Peterson Mar. l5, 1949
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|U.S. Classification||222/46, 222/390, 422/925, 422/511|