EP1195200A2 - Pipette avec un piston mouvant à la vitesse uniforme - Google Patents

Pipette avec un piston mouvant à la vitesse uniforme Download PDF

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Publication number
EP1195200A2
EP1195200A2 EP01123092A EP01123092A EP1195200A2 EP 1195200 A2 EP1195200 A2 EP 1195200A2 EP 01123092 A EP01123092 A EP 01123092A EP 01123092 A EP01123092 A EP 01123092A EP 1195200 A2 EP1195200 A2 EP 1195200A2
Authority
EP
European Patent Office
Prior art keywords
piston
cylinder
delivery
pipette
cross
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP01123092A
Other languages
German (de)
English (en)
Other versions
EP1195200A3 (fr
Inventor
Walter Lutz
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Walu Labortechnik GmbH
Original Assignee
Walu Labortechnik GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Walu Labortechnik GmbH filed Critical Walu Labortechnik GmbH
Publication of EP1195200A2 publication Critical patent/EP1195200A2/fr
Publication of EP1195200A3 publication Critical patent/EP1195200A3/fr
Withdrawn legal-status Critical Current

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Classifications

    • 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
    • B01L3/021—Pipettes, i.e. with only one conduit for withdrawing and redistributing liquids
    • B01L3/0217—Pipettes, i.e. with only one conduit for withdrawing and redistributing liquids of the plunger pump type

Definitions

  • the invention relates to a pipette for receiving and dispensing a liquid.
  • Such pipettes are already known. They generally have one in one Cylinder with longitudinally displaceable pistons.
  • the piston can be actuated, usually by hand, but sometimes also by motor.
  • the piston is normally connected to a piston rod, which has an operating button protrudes from the housing of the pipette.
  • the piston which can also be designed as a plunger, from which Cylinder moved out.
  • This movement can be done by a spring, usually a compression spring, supported or caused.
  • the pressure stroke executed in which the piston, possibly against the force of the mentioned Spring or compression spring, is moved into the cylinder, which is due to a pressure can happen on the push button. The first sucked into the cylinder Liquid is then released again.
  • the dosing accuracy of such pipettes depends on the cross-sectional area or the diameter of the piston, the piston stroke and the suction speed.
  • the possibilities of influencing the improvement of the dosing accuracy are however limited.
  • the piston stroke is essentially due to human anatomy set because the control button usually by the thumb of the the housing of the pipette is held by hand.
  • the dosing piston stroke is accordingly limited by the freedom of movement of the thumb.
  • the suction speed and also the delivery speed are subject to the immediate Operator influence. This is the main cause of the sources of error the dosage.
  • the pipette according to the preamble of claim 1 has a delivery cylinder in which a delivery piston is preferably guided in a longitudinally displaceable manner.
  • the Cross-sectional area that is in a delivery cylinder / delivery piston with a circular Cross section determined by its radius or diameter is greater than the cross-sectional area of the piston.
  • the pipette points to the preamble of the claim 2 a delivery piston preferably guided in a longitudinally displaceable manner in a delivery cylinder whose cross-sectional area or whose radius / diameter is larger than the cross-sectional area or the radius / diameter of one in a dosing cylinder preferably longitudinally guided, connected to the piston Metering.
  • Both solutions make a hydraulically or pneumatically translated dosing technology created. Because the cross-sectional area or the radius / diameter of the delivery piston is larger than the cross-sectional area or Radius / diameter of the piston or the metering piston is achieved that the Piston stroke or dosing piston stroke is greater than the stroke of the delivery piston. By each of the different cross-sectional areas or diameters mentioned can be used desired translation can be achieved. It is possible that the speed of the piston or dosing piston, by which the speed of the recording and delivery of the liquid is determined differently, namely is greater than the speed of the delivery piston, determined by the speed of its Actuation is determined. This results in a larger piston stroke or metering piston stroke reached.
  • a return spring is present, which the piston or the Dosing piston preloaded in the direction of the suction stroke.
  • the return spring is preferred a compression spring.
  • an overflow channel from the delivery cylinder to the cylinder or to the dosing cylinder is provided in the line.
  • the overflow channel is preferably designed as a throttle channel. This makes it possible to make differences in the operating speed of the Compensate the delivery piston.
  • the flow velocity in the overflow channel or throttle channel is independent of speed differences of the Delivery plungers are essentially the same so that the rate of liquid discharge and / or the rate of fluid intake during the Suction stroke is evened out, even if the suction stroke through a return spring is supported or effected.
  • the cross section of the overflow channel or throttle channel is adjustable.
  • the setting can be made, for example, using an adjusting screw, which protrudes into the cross section of the overflow channel or throttle channel.
  • throttle check valve in the line from the delivery cylinder to the cylinder or dosing cylinder
  • the throttle check valve is preferably installed in such a way that it closes during the suction stroke and opens during the pressure stroke. While the suction stroke is then a flow path from the feed cylinder to the cylinder or dosing cylinder only opened via the overflow channel or throttle channel, whereby the suction speed is essentially fixed.
  • the overflow channel or throttle channel can be in the throttle check valve, preferably in its Middle. Additional overflow channels can occur during the pressure stroke be opened. This makes it possible to increase the pressure stroke and thus the delivery of the To effect liquid at a greater rate.
  • the pipette comprises a housing 1, which has a sleeve 2 at its front end is provided, which is connected to the housing 1 by a snap connection and which surrounds a cylinder 3.
  • the cylinder 3 is in the front end of the housing 1 inserted and surrounded in its outer area by the sleeve 2.
  • a piston 4 is guided in a longitudinally displaceable manner in the cylinder 3.
  • the piston 4 is a component a piston part 9 which, in addition to the piston 4, also has a diameter Larger middle part 12, a piston rod 11 and a metering piston 10 consists.
  • the middle part 12 is connected to a stop part 5, the one after outside (in the single figure downward) stop 6 for a as Compression spring trained return spring 7, the other end to a paragraph 8 of the cylinder 3 supports.
  • the metering piston 10 is through the piston rod 11 with the central part 12 of the piston part 9 connected. It is guided so as to be longitudinally displaceable in a metering cylinder 13. It is sealed off from this metering cylinder 13 by a piston ring 14.
  • the dosing cylinder 13 is fastened in an eye 15 of the housing 1.
  • the piston part 9 is provided on the stop part 5, inwards (in the single Figure upward) protruding bush 16, with its inner surface on the outer surface of the metering cylinder 13 abuts, slidably mounted.
  • a feed cylinder 17 is also inserted, in which a delivery piston 18, which is sealed by a piston ring 19, is longitudinally displaceable is stored.
  • the delivery piston 18 is connected via a piston rod 20 to a Push button 21 connected, the one facing the delivery piston 18 socket 22nd has, whose inner surface abuts the outer surface of the feed cylinder 17 and is slidably guided there.
  • the suction stroke of the delivery piston 18 is by the Socket 22 limits outward-facing stop ring 23.
  • the pressure stroke is limited by steps 24 of the socket 22, which are on a guide 25 for an adjusting screw Strike 26. By rotating the bush 22, the desired one Level 24 can be selected.
  • a throttle check valve 28 In a bottom surface 27 of the feed cylinder 17, which is in its lower region is a throttle check valve 28 is used.
  • the throttle check valve 28 has a valve body 29, in which a central (central) overflow channel 30, which is designed as a throttle channel, is provided.
  • the material of the valve body 29 is compressible. This is on the outside of the valve body End of the adjusting screw 26. By moving the set screw 26 can the valve body 29 are compressed, causing the cross section of the overflow channel 30 can be changed in this area. In this way the flow rate in the overflow channel 30 through the adjusting screw 26 can be changed.
  • the set screw 26 has an external thread with a corresponding Internal thread cooperates inside the guide 25.
  • the guide 25 is part of the delivery cylinder 17.
  • the delivery cylinder 17 is also through the guide 25 connected to the housing 1.
  • the valve body 29 is mushroom-shaped on its side facing the metering piston 10 designed. There it has an essentially circular cap, which in the bottom surface 27 of the delivery cylinder 17 covers provided openings 31.
  • the outer edge of the mushroom-shaped part of the valve body 29 is, however, elastic, so that the flow path through the openings 31 through deformation of the mushroom-shaped part of the valve body 29 can be opened.
  • the one that is plugged onto the lower end of the cylinder 3 is first Protective cap 32 removed. This can be done by a tip ejection mechanism.
  • a sliding part 33 is mounted to be longitudinally displaceable by pushing the recessed grip 34 against the force of a compression spring 35 is.
  • the compression spring 35 is at its lower end on a part of the housing 1 supported. With its upper end it presses on a part of the sliding part 33.
  • the sliding part 33 is connected to the sleeve 2 via a barb connection 36 connected. When the sliding part 33 is pressed down, it also moves the sleeve 2 down. Its lower end surface presses on the upper end surface of the Protective cap 32 and moves it downward from the cylinder 3.
  • In the opening 37 of the cylinder 3 can be a tube or tube or glass tube be plugged in.
  • the push button 21 pressed down.
  • the delivery piston 18 moves downward.
  • the Liquid located in the delivery cylinder 17 flows through the overflow channel 30.
  • the overpressure in the feed cylinder 17 also causes the mushroom-shaped part of the valve body 29 is opened so that the flow path through the openings 31st becomes free.
  • the liquid flows from the delivery cylinder 17 through the overflow channel 30 and the openings 31 in the metering cylinder 13. It presses the metering piston 10 and thus also the piston 4 connected to it downwards.
  • the lower end position is reached, which is determined by the steps 24 and the guide 25 the glass tube can be immersed in the liquid.
  • the push button 21 can be released.
  • the piston part 9 moves through the action of the return spring 7 upwards.
  • the movement of the piston 4 is caused by the movement of the latter connected metering piston 10 determines its movement by itself the cross-sectional area of the overflow channel 30 is determined.
  • the mushroom-shaped part of the valve body 29 in brought the position shown in the single figure, in which the openings 31 closed are.
  • the only flow path between dosing cylinder 13 and delivery cylinder 17 is accordingly opened by the overflow channel 30.
  • the cross-sectional area of the overflow channel 30 can be changed by the adjusting screw 26 or adjusted. Through the overflow channel designed as a throttle channel 30 becomes the speed of the metering piston 10 and thus the speed the piston 4 smoothed.
  • a pressure is exerted on the push button 21 to dispense the liquid.
  • the Mushroom-shaped part of the valve body 29 opens again.
  • the liquid flows from the feed cylinder 17 through the overflow channel 30 and the openings 31 in the Dosing cylinder 13.
  • the piston 4 moves at a constant speed down, so that the dispensing of the absorbed liquid also is evened out.
  • the invention creates a pipette in which the metering speed Regulated independently of the thumb movement via a throttle check valve can be.
  • a delivery piston 18 with a larger cross section acts via overflow channels 30, 31 on an adjustable throttle check valve 28 on an in Cross-section smaller metering piston 10, whereby the metering piston 10 has a larger one Piston stroke executes as the delivery piston 18.
  • the piston stroke of the metering piston 10 is limited by fixed or variable stops.
  • the top stop is through a stop inside the stop part 5 on the lower end of the metering cylinder 13 causes.
  • the lower stop is the stop of the lower end the stop part 5 is fixed to the upper end of the cylinder 3.

Landscapes

  • Health & Medical Sciences (AREA)
  • Clinical Laboratory Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Devices For Use In Laboratory Experiments (AREA)
  • Reciprocating Pumps (AREA)
  • Feeding, Discharge, Calcimining, Fusing, And Gas-Generation Devices (AREA)
  • Sampling And Sample Adjustment (AREA)
EP01123092A 2000-10-06 2001-09-26 Pipette avec un piston mouvant à la vitesse uniforme Withdrawn EP1195200A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE10049507 2000-10-06
DE2000149507 DE10049507B4 (de) 2000-10-06 2000-10-06 Pipette

Publications (2)

Publication Number Publication Date
EP1195200A2 true EP1195200A2 (fr) 2002-04-10
EP1195200A3 EP1195200A3 (fr) 2003-11-19

Family

ID=7658887

Family Applications (1)

Application Number Title Priority Date Filing Date
EP01123092A Withdrawn EP1195200A3 (fr) 2000-10-06 2001-09-26 Pipette avec un piston mouvant à la vitesse uniforme

Country Status (2)

Country Link
EP (1) EP1195200A3 (fr)
DE (1) DE10049507B4 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111957362A (zh) * 2020-08-13 2020-11-20 温州市人民医院 一种批量吸样装置

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102010038414A1 (de) 2010-07-26 2012-01-26 Hamilton Bonaduz Ag Pipettiervorrichtung mit Drosselstelle im Pipettierkanal
DE102017008528A1 (de) 2017-09-12 2019-03-14 Brand Gmbh + Co Kg Pipette mit einer Betätigungseinrichtung

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3935734A (en) * 1975-02-26 1976-02-03 Keegan William P Pipettes
DE2651333A1 (de) * 1976-11-10 1978-05-11 Sarstedt Kunststoff Saugpipette
EP0737515A1 (fr) * 1995-04-12 1996-10-16 Labsystems Oy Pipette à plusieurs phases de fonctionnement

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3935734A (en) * 1975-02-26 1976-02-03 Keegan William P Pipettes
DE2651333A1 (de) * 1976-11-10 1978-05-11 Sarstedt Kunststoff Saugpipette
EP0737515A1 (fr) * 1995-04-12 1996-10-16 Labsystems Oy Pipette à plusieurs phases de fonctionnement

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111957362A (zh) * 2020-08-13 2020-11-20 温州市人民医院 一种批量吸样装置

Also Published As

Publication number Publication date
DE10049507A1 (de) 2002-04-11
EP1195200A3 (fr) 2003-11-19
DE10049507B4 (de) 2009-08-20

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