US3756458A - Burettes and pipettes - Google Patents

Burettes and pipettes Download PDF

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Publication number
US3756458A
US3756458A US00006440A US3756458DA US3756458A US 3756458 A US3756458 A US 3756458A US 00006440 A US00006440 A US 00006440A US 3756458D A US3756458D A US 3756458DA US 3756458 A US3756458 A US 3756458A
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United States
Prior art keywords
nozzle
liquid
outlet
side wall
gas
Prior art date
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Expired - Lifetime
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US00006440A
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English (en)
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M Fill
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Individual
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Individual
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L3/00—Containers or dishes for laboratory use, e.g. laboratory glassware; Droppers
    • B01L3/02—Burettes; Pipettes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L2200/00—Solutions for specific problems relating to chemical or physical laboratory apparatus
    • B01L2200/06—Fluid handling related problems
    • B01L2200/0615—Loss of fluid by dripping
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L2400/00—Moving or stopping fluids
    • B01L2400/02—Drop detachment mechanisms of single droplets from nozzles or pins

Definitions

  • ABSTRACT Method and device for dispensing a predetermined amount of liquid which includes a storage means for holding liquid therein, a nozzle for dispensing the liquid from the storage means, and means for producing a symmetrical puff of gas about the nozzle side wall to remove droplets from the outlet of the nozzle.
  • the present invention relates to burettes, pipettes, syringes and the like.
  • the invention provides a method for removing droplets from the tip of the delivery nozzle of burettes, pipettes, syringes, and the like, or for stirring liquid into which the tip of said delivery nozzle projects, which comprises directing a puff of gas past said tip in the direction of delivery of liquid through said nozzle in such a manner as to symmetrically surround said tip.
  • This method is effected by a device having a gas passage therein, an inlet to said passage adapted to be supplied with pressurised gas, and anoutlet directed in the delivery direction of said delivery nozzle and arranged to allow egress of said pressurised gas adjacent to and symmetrically surrounding the tip of said delivery nozzle.
  • the method is performed by applying a short flow or puff of gas after the main delivery of the liquid has been completed, the fiow or puff of gas being of sufficient intensity to blow off substantially all adhering liquid.
  • the effect is to take the level of the liquid at the delivery nozzle always to a definite level.
  • a puff of gas before delivery effects an adjustment of the liquid to this definite level, and a puff after a measured volume has been dispensed returns the liquid to the same level.
  • the volume of liquid which haspassed out of the apparatus thus accurately corresponds to the volume measured and no allowance or corrections have to be made for liquid adhering to the nozzle.
  • a preferred embodiment of the device of the invention comprises a cylindrical member for mounting coaxial with the delivery nozzle, to be spaced therefrom so as to provide an annular chamber, the end of the cylindrical member remote from the tip of the delivery nozzle fitting the nozzle tightly.
  • the cylindrical member is conveniently provided with a side-tube as the inlet through which the gas can be applied, and has an outlet adjacent to and symmetrically surrounding the tip of the delivery nozzle.
  • the side-tube preferably incorporates a valve, thereby preventing any suck-back of the gas after a puff, and it is convenient for the valve to be a press-button valve which is operated each time a puff of gas is required.
  • the tip of the delivery nozzle of any burette, pipette, syringe or the like, forming part of the device, or to which the device is attached, is most desirably provided with a chisel-edge, and is preferably coplanar with the outlet of the cylindrical member.
  • An alternative embodiment is one in which instead of an annular chamber around the delivery nozzle constituting the gas passage, the gas passage is contained within the walls of the cylindrical member, and thus the device need not touch the delivery nozzle.
  • the gas used in operation of the device of the invention may be air, and the air can be applied conveniently from a source of compressed air such as a handoperated bulb or syringe.
  • a source of compressed air such as a handoperated bulb or syringe.
  • gases are nitrogen, carbon dioxide, or an inert gas such as argon.
  • Sterile air may also be used when it is desirable to operate the device under sterile conditions.
  • the device of the invention is particularly useful in combination with a micrometer syringe, such as that sold under the registered trade-mark Agla.
  • the delivery nozzle comprises a syringe needle, around which the cylindrical member is positioned.
  • the capillary of the needle is of a very fine bore, and the finer the bore, the greater is the gas pressure require to remove the droplets; conversely, if the syringe is fitted with a shorter needle, the gas pressure required is decreased.
  • the invention therefore'provides a means of obtaining a very high order of accuracy of dispensing liquid in a microtitration, particularly for volumes of liquid less than 500 microlitres.
  • a microtitration When a microtitration is performed the needle is cleared initially with a puff of gas; when the microtitration is performed with the needle above the surfaceof the solution inthereceiving vessel, each drop-of liquid delivered can be blown off by subsequent discharges of the gas..Thus liquid can be dispensed under sterile conditions, and the need for any contact with the sides of the receiving vessel is obviated.
  • the invention also provides a means of dispensing accurate volumes of liquid in chromatography procedures.
  • the needle is held close to, but not in contact with, the support medium.
  • the device of the invention provides a means for increasing the accuracy of dispensing liquid from a burette, pi-
  • the device is most conveniently constructed as an adaptor for sliding onto the conical delivery nozzle of the measuring device.
  • the invention also provides a means for stirring a liquid, the flow of gas through the liquid or onto the surfacesimulating mechanical agitation.
  • FIG. 1 is a vertical cross-section of a syringe in combination with a device according to the invention
  • FIG. 2 is a cross-sectionof the tip of the syringe shown in FIG. 1;
  • FIG. 3 is a vertical cross-section of a burette in combination with an alternative form of a device according to a side-tube 7 fitted with a valve 8.
  • Side-tube 7 is connected to a hand-operated bulb 9 of compressed air by rubber tubing 10.
  • Chamber has an outlet 11 adjacent to and surrounding the tip 12 of the syringe needle 3.
  • the syringe 1 can be positioned in a horizontal plane, in which case the cylindrical member 4 and the syringe needle 3 may be extended and curved so that the tip 12 of the needle 3 is directedly vertically for delivery. It is often convenient to use a straight needle 3, fitted to the syringe l by means of a curved metal tube.
  • FIG. 2 shows the tip 12 of the syringe needle 3, the tip 12 having a chisel-edge 13 to facilitate the removal of adhering liquid.
  • the conical-shaped delivery nozzle 14 of a burette 15 is surrounded by a coaxial member 16.
  • the upper end of the coaxial member 16 has a tapered opening adapted to fit precisely onto the tapered delivery nozzle 14.
  • the same reference numerals as those used in FIG. 1 and 2 are employed here where applicable.
  • the side-arm 7 is connected by rubber tubing to a source of pressurised gas (not shown in this Figure).
  • FIG. 4 shows the delivery nozzle 17 of a measuring device (not shown in this Figure), the nozzle 17 projecting into a liquid 18 is contained in a vessel 19.
  • a device for delivering measured amounts of liquid comprising storage means for storing a quantity of liquid, nozzle means coupled to said storage means, said nozzle means having an outer side wall and a central bore with an outlet at the terminus of the bore, means for dispensing a measured amount of liquid from the storage means through the central bore of said nozzle, means for measuring the quantity of liquid dispensed, a hollow cylindrical member having an inner side wall, said cylindrical member, inner side wall and said nozzle outer side wall defining an annular chamber, said annular chamber extending about the nozzle outer side wall and spaced therefrom and which also extends towards the outlet of the nozzle but not below the outlet of the nozzle, said annular chamber only permitting the escape of gas from the chamber in the direction of the outlet and about the nozzle outer side wall, a tube extending into the annular chamber, and means for producing a puff of compressed gas coupled to said tube in order to produce a symmetrical puff of gas flow between the outer said wall of the nozzle and the inner side wall of the hollow cylindrical member to effect removal of liquid
  • the storage means comprises asyringe
  • the means for dispensing comprises a syringe plunger
  • the nozzle comprises a needle
  • the cylindrical member surrounds and is supported by a portion of the syringe.
  • a device in which the needle extends past the end of the hollow cylindrical member.
  • a device in which a valve is provided in the tube to only permit the flow of gas into the annular chamber.
  • a device in which a hand operable bulb is coupled to the tube.
  • a device in which the nozzle extends past the end of the hollow cylindrical member.
  • a device in which a valve is provided in the tube to only permit the flow of gas into the annular chamber.
  • a device in which the nozzle includes a chisel edge at the end thereof about the outlet.

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  • Health & Medical Sciences (AREA)
  • Clinical Laboratory Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Sampling And Sample Adjustment (AREA)
  • Feeding, Discharge, Calcimining, Fusing, And Gas-Generation Devices (AREA)
  • Devices For Use In Laboratory Experiments (AREA)
US00006440A 1969-02-03 1970-01-28 Burettes and pipettes Expired - Lifetime US3756458A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB565569 1969-02-03

Publications (1)

Publication Number Publication Date
US3756458A true US3756458A (en) 1973-09-04

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ID=9800146

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Application Number Title Priority Date Filing Date
US00006440A Expired - Lifetime US3756458A (en) 1969-02-03 1970-01-28 Burettes and pipettes

Country Status (4)

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US (1) US3756458A (enrdf_load_stackoverflow)
DE (1) DE7003472U (enrdf_load_stackoverflow)
GB (1) GB1305376A (enrdf_load_stackoverflow)
SE (1) SE377500B (enrdf_load_stackoverflow)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3341283A1 (de) * 1983-11-15 1985-05-23 Artur Dr.H.C. 7244 Waldachtal Fischer Behaelter zum ausspritzen eines bindemittels fuer die verankerung eines befestigungselementes in einem bohrloch
DE3405352A1 (de) * 1984-02-15 1985-08-22 Paul Dr.med. 4300 Essen Behrendt Vorrichtung zum applizieren pastoeser stoffe, insbesondere pharmazeutischer oder kosmetischer praeparate
DE3733521A1 (de) * 1987-10-03 1989-05-03 Neumann Wolfgang N Treibgasfreie spruehdose
US5261566A (en) * 1981-02-16 1993-11-16 Tokyo Ohka Kogyo Co., Ltd. Solution-dropping nozzle device
CN107552102A (zh) * 2016-06-30 2018-01-09 天津市亨必达化学合成物有限公司 一种容量瓶用加液管
CN107552101A (zh) * 2016-06-30 2018-01-09 天津市亨必达化学合成物有限公司 一种容量瓶

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2354555A1 (fr) * 1976-06-08 1978-01-06 Technicon Instr Pipette pour aspirer des liquides pour l'analyse d'echantillons

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2721147A (en) * 1955-10-18 Method and apparatus for coating
US2987221A (en) * 1957-08-29 1961-06-06 Union Carbide Corp Powder ejector assembly
US3176883A (en) * 1963-04-15 1965-04-06 Jr George B Davis Fluid dispenser
US3228412A (en) * 1962-07-16 1966-01-11 Bartelt Engineering Co Inc Dispensing valve having particular cleaning means

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2721147A (en) * 1955-10-18 Method and apparatus for coating
US2987221A (en) * 1957-08-29 1961-06-06 Union Carbide Corp Powder ejector assembly
US3228412A (en) * 1962-07-16 1966-01-11 Bartelt Engineering Co Inc Dispensing valve having particular cleaning means
US3176883A (en) * 1963-04-15 1965-04-06 Jr George B Davis Fluid dispenser

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5261566A (en) * 1981-02-16 1993-11-16 Tokyo Ohka Kogyo Co., Ltd. Solution-dropping nozzle device
DE3341283A1 (de) * 1983-11-15 1985-05-23 Artur Dr.H.C. 7244 Waldachtal Fischer Behaelter zum ausspritzen eines bindemittels fuer die verankerung eines befestigungselementes in einem bohrloch
DE3405352A1 (de) * 1984-02-15 1985-08-22 Paul Dr.med. 4300 Essen Behrendt Vorrichtung zum applizieren pastoeser stoffe, insbesondere pharmazeutischer oder kosmetischer praeparate
DE3733521A1 (de) * 1987-10-03 1989-05-03 Neumann Wolfgang N Treibgasfreie spruehdose
CN107552102A (zh) * 2016-06-30 2018-01-09 天津市亨必达化学合成物有限公司 一种容量瓶用加液管
CN107552101A (zh) * 2016-06-30 2018-01-09 天津市亨必达化学合成物有限公司 一种容量瓶

Also Published As

Publication number Publication date
SE377500B (enrdf_load_stackoverflow) 1975-07-07
GB1305376A (enrdf_load_stackoverflow) 1973-01-31
DE7003472U (de) 1970-10-08

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