EP2125225A1 - Apparatus and method for dosing liquids into gas-filled chambers - Google Patents
Apparatus and method for dosing liquids into gas-filled chambersInfo
- Publication number
- EP2125225A1 EP2125225A1 EP08708927A EP08708927A EP2125225A1 EP 2125225 A1 EP2125225 A1 EP 2125225A1 EP 08708927 A EP08708927 A EP 08708927A EP 08708927 A EP08708927 A EP 08708927A EP 2125225 A1 EP2125225 A1 EP 2125225A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- volume
- valve
- pump
- liquid
- shut
- 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- Withdrawn
Links
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
- B01L3/0241—Drop counters; Drop formers
- B01L3/0265—Drop counters; Drop formers using valves to interrupt or meter fluid flow, e.g. using solenoids or metering valves
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B43/00—Machines, pumps, or pumping installations having flexible working members
- F04B43/08—Machines, pumps, or pumping installations having flexible working members having tubular flexible members
- F04B43/084—Machines, pumps, or pumping installations having flexible working members having tubular flexible members the tubular member being deformed by stretching or distortion
-
- 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
- B01L2200/00—Solutions for specific problems relating to chemical or physical laboratory apparatus
- B01L2200/14—Process control and prevention of errors
- B01L2200/143—Quality control, feedback systems
- B01L2200/146—Employing pressure sensors
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
- B01L2300/00—Additional constructional details
- B01L2300/14—Means for pressure control
-
- 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
- B01L2400/04—Moving fluids with specific forces or mechanical means
- B01L2400/0475—Moving fluids with specific forces or mechanical means specific mechanical means and fluid pressure
- B01L2400/0481—Moving fluids with specific forces or mechanical means specific mechanical means and fluid pressure squeezing of channels or chambers
-
- 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
- B01L2400/06—Valves, specific forms thereof
- B01L2400/0633—Valves, specific forms thereof with moving parts
- B01L2400/0655—Valves, specific forms thereof with moving parts pinch valves
Definitions
- the present invention relates to an apparatus and method for dosing liquids in gas-filled spaces. Such methods and devices are used, for example, in analysis technology, wherein analytes or reagents are to be dosed. Dosing of liquids is generally intended to serve the purpose of transferring a defined volume of a substance to a destination, such as a reactor or analyzer.
- Dosing devices for this usually consist of the following components, which are interconnected and arranged one behind the other in the flow direction: a pump inlet, which is connected to a source, a pump, a pump discharge and a metering orifice. If the metering orifice does not flow into a liquid medium but into a gaseous (for example into an air-filled reactor), the liquid passes in a jet or dropwise into the reactor. It is often desired to settle the liquid in free fall into a target zone of the reactor, without the liquid having contact with the reactor wall.
- the last drop in a total of N drops is metered with only a certain probability, the relative uncertainty is 1 / N. For a total amount corresponding to a volume of, for example, 20 drops, this uncertainty would mean a relative inaccuracy of 5%. This is unacceptable in many cases.
- the question of whether a drop is now metered with, thus dissolves from the metering depends on the particular circumstances of each arrangement, for example, the drop size, the viscosity, the surface tension, the metering speed, and the geometry of the metering. In addition, random vibration or vibration of the arrangement may be the deciding factor. As far as that is The question of whether the last drop is dosed, more or less left to chance.
- the pipette tip When pipetting can be first dosed into a target vessel, the pipette tip is held at least towards the end of dosing to the inner wall of the target vessel so that the surface energy of the inner wall facilitates the replacement of the last drop.
- this approach is only partially accessible to automation and is completely ruled out if the substance to be dosed should reach the target vessel in free fall, ie without wall contact.
- the substance to be dosed with a larger volume of a carrier gas can be injected into a target vessel, for example with a piston stroke pipette.
- the disadvantage here is the uncontrolled wetting of surfaces in the target vessel, which can lead to carry-over and poor reproducibility, especially in long-term operation.
- due to the compressibility of the carrier gas due to the compressibility of the carrier gas, a pressure dependence of the dosing accuracy is given, which requires a greater sensory effort.
- the dosage can be done by an (injection) nozzle with increased speed. This procedure is not bad in itself, but can not be realized with peristaltic pumps, since they do not build up the required pressure. Nozzles are also responsible for particle-containing liquids due to the risk of clogging.
- the invention is therefore based on the object to provide a simple and accurate metering device, which in particular includes the possibility of using a peristaltic pump, and which is particularly suitable for processes that require dropwise metering of samples or reagents in a reaction vessel, For example, where the allowable deviation from the setpoint is less than the volume of a single drop. Furthermore, a corresponding metering method is to be specified, which addresses the disadvantages of the prior art technology overcomes.
- the object is achieved by the device according to the independent claim 1 and by the method according to independent claim 13.
- the inventive device for dosing liquids in a gas-filled space comprises a pump; a metering opening for introducing the liquid into the gas-filled space, a line which connects a pressure side of the pump with the metering, an elastic liquid storage, characterized in that the conduit has a shut-off valve between the pump and the metering, wherein the elastic liquid storage between the Pump and the shut-off valve is arranged, wherein the device has a first operating state in which the pump runs when the shut-off valve is closed to store in the elastic liquid reservoir, a quantity of liquid under pressure.
- the device may comprise a second operating state in which the pump is switched off with the liquid reservoir under pressure with the shut-off valve closed.
- the device further comprises a third operating state, in which the shut-off valve is opened when the pump is switched off, to allow liquid to flow out of the elastic liquid reservoir.
- the device may include a fourth operating state in which the shut-off valve is open when the pump is running.
- the device may include a control unit which controls the operating conditions described and the transition between the operating states.
- the control unit preferably includes a microprocessor integrated with the aforementioned components in a device, for example, but may also include an external computer that communicates with the other components via a data line or wirelessly.
- the device is brought into the first operating state, and held in this state until the elastic liquid storage has taken up the missing volume under pressure. Then, the device is brought from the first operating state of the first operating state immediately after the second and third operating state or directly from the first operating state to the third operating state, whereby the pressurized elastic liquid storage is expanded by expelling the missing liquid volume.
- the elastic liquid storage can be realized in the simplest case by the line itself, which includes, for example, an elastic hose of a peristaltic pump.
- the length of the hose section between the pump and shut-off valve is to be dimensioned so that the relative increase in volume of the hose by pumping the missing volume with closed shut-off valve against the equilibrium volume, ie the volume of the relaxed liquid-filled tube section, leads to a sufficient increase in pressure so the lack of liquid volume is discharged after opening the shut-off valve with a sufficient speed.
- the relative volume change due to the inclusion of the missing fluid volume relative to the equilibrium volume of the hose section between pump and shut-off valve may be, for example, between about 5% and about 20% and between about 10% and about 15% of the equilibrium volume.
- the elastic liquid reservoir may also include an elastic container, such as bellows, which is connected to a rigid conduit communicated.
- the elastic liquid reservoir comprises a rigid conduit in which a compressible filling body is arranged. Similar dimensions as in the case of the elastic hose are to be made analogously.
- the control unit can the dosage in particular of the missing
- time-controlled volume For example, time-controlled volume.
- the monitoring of the dosage of the missing volume in the first operating state via a pressure sensor which monitors the pressure in the elastic liquid storage, or monitored by a deformation sensor, for example, the elongation of an elastic tubing.
- a flow sensor can be used which monitors the delivered quantity.
- the shut-off valve may be configured in a simple configuration as a pinch valve, but there are also any other valve types possible. However, it is advantageous that the valve can be opened and / or closed quickly.
- the shut-off valve comprises a magnetically switched pinch valve, which quickly closes the hose when a current is applied to a solenoid and releases the flow at a similar speed when the current is switched off.
- the term “fast” refers to the time to open or close the tubing relative to the metering time of the volume of a drop while the pump is running and the tubing is open, so that it opens or closes rapidly if it is less than 1%, preferably less than , 5% and more preferably less than 0.25% of the metering time of a drop volume under the conditions mentioned.
- the metering opening may comprise, for example, the opening of a cannula, in particular a stainless steel or glass cannula.
- the shut-off valve is preferably arranged as close as possible to the metering opening.
- the inventive method for dosing liquids in a gas-filled space comprising the steps: operating a pump to promote a defined amount of liquid via a line in an elastic liquid storage, which has a defined overpressure upon reaching the defined amount of liquid, the line by means of a shut-off valve opposite a metering orifice is closed, and wherein the elastic liquid storage is arranged between the pump and the shut-off valve; and opening the shut-off valve when the pump is switched off, so that the liquid reservoir discharges the defined amount of liquid, wherein the stored liquid emerges from the elastic pressure accumulator due to the increased pressure in the accumulator at such a speed that a corresponding amount of the liquid emerging from the metering orifice due to its speed overcomes the adhesion forces to the dosing and peels off.
- the period of time for which the pump is operated when the shut-off valve is closed is preferably selected so that builds up a sufficient pressure in the elastic liquid storage, so that at the opening of the valve emerging at the metering defined amount of liquid is delivered in a single drop , Which dissolves completely by the speed of the exit of the metering, wherein possibly hanging on the metering orifice liquid droplets are entrained by the leaking liquid.
- the pump Before operating the pump with the shut-off valve closed, the pump can be operated at the beginning of the dosing with open shut-off valve to output a defined basic volume before the shut-off valve is closed, wherein the pumped with the shut-off valve in the elastic pressure accumulator volume defined Residual volume to complete a total volume.
- the base volume and the residual volume together give a single drop that dissolves from the metering.
- the drops produced in this way may possibly be significantly smaller than drops that through ordinary pumps are discontinued from the Doserö Anlagen.
- the method offers an alternative to dosing through narrow nozzles, which also allow the settling of small drops, but can easily clog on liquids with pollution load.
- the base volume is not more than 8 times, preferably not more than 4 times, more preferably not more than 2 times, and most preferably not more than 1 times of the remaining volume.
- the steps for dispensing a target volume alternately the steps for dispensing the base volume and the dosage of the remaining volume, which together give a defined total volume, are repeated until the multiple of the total volume corresponds to the target volume ,
- the base volume may
- Volume of several drops include, and the residual volume serve to dissolve at the exit at an increased speed, possibly remaining at the metering drops from the output of the base amount.
- the device is particularly suitable for dosing reagents or samples in the volume range of ⁇ l and ml, for example, aqueous samples in reactors of devices for the determination of analysis parameters, such as TOC.
- the dosage rates may be, for example, in the range of about 1 to about 10 ⁇ l / sec.
- a pump can promote a given volume through an elastic hose to a metering, wherein the valve is opened from the beginning of the dosage, just before the completion of the dosage while still running Pump is closed and finally at the time when the pump stops pumping, is opened again.
- the period of time for which the valve is closed is chosen so that a sufficient pressure builds up in the elastic tube, so that the remaining amount of the volume to be dispensed at the opening of the valve in a single drop is released, which dissolves completely by the speed of the exit of the metering.
- the valve is periodically after the promotion of a certain volume, which is less than the volume of a single drop in uninterrupted production, closed and reopened.
- the period of time for which the valve is closed is chosen so that a sufficient pressure builds up in the elastic tube, so that the droplets formed at the dosing issued together with the volume accumulated in the elastic tube at the opening of the valve in a single drop is, which dissolves completely by the speed of the exit of the metering.
- Fig. 1 A block diagram of a device according to the invention.
- the metering device shown in Fig. 1 comprises a peristaltic pump 1 and a metering orifice 2 at the end of a few cm long steel cannula with an inner diameter of about 1 mm.
- On this cannula is the end portion of an elastic tube 3 wherein the tube passes through the peristaltic pump 3, to promote through it a liquid to the metering orifice.
- the hose can be, for example, a BPT hose available from Saint Gobain under the brand name PHARMED for peristaltic pumps.
- the inner diameter is about 0.76 mm.
- the tube can be closed abruptly in its end portion near the cannula with a magnetically controlled pinch valve 5 and released again.
- the hose also serves as an elastic liquid reservoir 4, which can absorb more liquid under pressure with closed pinch valve, as in the relaxed state of equilibrium. This is the controlled dosing and detachment of defined drops possible, as will now be explained.
- the tube section between the pump 1 and the valve 5 has a length of about 9 cm, which corresponds to an equilibrium volume of about 41 .mu.l.
- the additional 5 ⁇ l thus means an increase of the tube volume by about 12% or an average elastic expansion of the tube circumference by about 6%.
- the pressure increase required for stretching the hose is sufficient to push the additional 5 ⁇ l out of the hose so quickly after switching off the pump and opening the valve that the corresponding quantity of fluid flowing out of the metering opening 2 is fast enough to increase the adhesive forces to the cannula to overcome and replace the previously funded 20 ul with.
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Health & Medical Sciences (AREA)
- Clinical Laboratory Science (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Feeding, Discharge, Calcimining, Fusing, And Gas-Generation Devices (AREA)
- Infusion, Injection, And Reservoir Apparatuses (AREA)
Abstract
Description
Claims
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE102007007658 | 2007-02-13 | ||
DE102007010412.1A DE102007010412B4 (en) | 2007-02-13 | 2007-03-01 | Device and method for dosing liquids into gas-filled rooms |
PCT/EP2008/051700 WO2008098947A1 (en) | 2007-02-13 | 2008-02-13 | Apparatus and method for dosing liquids into gas-filled chambers |
Publications (1)
Publication Number | Publication Date |
---|---|
EP2125225A1 true EP2125225A1 (en) | 2009-12-02 |
Family
ID=39432839
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP08708927A Withdrawn EP2125225A1 (en) | 2007-02-13 | 2008-02-13 | Apparatus and method for dosing liquids into gas-filled chambers |
Country Status (5)
Country | Link |
---|---|
US (1) | US20100059549A1 (en) |
EP (1) | EP2125225A1 (en) |
CN (1) | CN101600502B (en) |
DE (1) | DE102007010412B4 (en) |
WO (1) | WO2008098947A1 (en) |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2018091075A1 (en) * | 2016-11-15 | 2018-05-24 | Tecan Schweiz Ag | Pipetting method and pipetting device |
DE102017110316B4 (en) * | 2017-05-12 | 2021-02-25 | Abb Schweiz Ag | Application device for coating components with a coating agent |
WO2019096993A1 (en) * | 2017-11-17 | 2019-05-23 | Eppendorf Ag | Micrometering device for the metering of very small fluid samples |
Family Cites Families (17)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3679331A (en) * | 1970-04-24 | 1972-07-25 | Delta Scient Corp | Metering pump and valve |
JPS49127207A (en) * | 1973-04-10 | 1974-12-05 | ||
US4181245A (en) * | 1978-02-17 | 1980-01-01 | Baxter Travenol Laboratories, Inc. | Casette for use with an I.V. infusion controller |
US4140020A (en) * | 1978-03-24 | 1979-02-20 | Syva Company | Seal-free pipette device |
US4515589A (en) * | 1981-03-23 | 1985-05-07 | Austin Jon W | Peristaltic pumping method and apparatus |
CN86210246U (en) * | 1986-12-15 | 1988-03-16 | 楼许柏 | Multipurpose liquid aspirator |
DE3705357A1 (en) * | 1987-02-19 | 1988-09-01 | Pfrimmer Viggo Gmbh Co Kg | DEVICE FOR ADMINISTERING LIQUID |
US5035350A (en) * | 1989-02-21 | 1991-07-30 | Minnesota Mining And Manufacturing Company | Method and apparatus for precision squeeze tube valving, pumping and dispensing of work fluid(s) |
US5029621A (en) * | 1990-04-12 | 1991-07-09 | Clintec Nutrition Co. | Push back procedure for preventing drop-former droplet formation in a vacuum assisted solution transfer system with upstream occulusion |
CN2103031U (en) * | 1991-08-26 | 1992-04-29 | 杨道成 | Automatic aspirating pump |
SE501000C2 (en) * | 1992-02-03 | 1994-10-17 | Jana System Ab | Liquid substance dispensing device |
US5433351A (en) * | 1992-05-01 | 1995-07-18 | Misuzuerie Co., Ltd. | Controlled liquid dispensing apparatus |
US20030207464A1 (en) | 1999-02-19 | 2003-11-06 | Tony Lemmo | Methods for microfluidic aspirating and dispensing |
IL148611A0 (en) | 1999-09-14 | 2002-09-12 | Pharmacopeia Inc | Flow control elements for use in liquid dispensers |
EP1220780A4 (en) | 1999-09-14 | 2004-03-24 | Pharmacopeia Inc | Article comprising a multi-channel dispensing head |
US7185551B2 (en) * | 2003-05-22 | 2007-03-06 | Schwartz H Donald | Pipetting module |
US7810677B2 (en) * | 2004-12-04 | 2010-10-12 | Medical Instill Technologies, Inc. | One-way valve and apparatus and method of using the valve |
-
2007
- 2007-03-01 DE DE102007010412.1A patent/DE102007010412B4/en active Active
-
2008
- 2008-02-13 US US12/449,452 patent/US20100059549A1/en not_active Abandoned
- 2008-02-13 EP EP08708927A patent/EP2125225A1/en not_active Withdrawn
- 2008-02-13 WO PCT/EP2008/051700 patent/WO2008098947A1/en active Application Filing
- 2008-02-13 CN CN2008800039894A patent/CN101600502B/en active Active
Non-Patent Citations (1)
Title |
---|
See references of WO2008098947A1 * |
Also Published As
Publication number | Publication date |
---|---|
DE102007010412B4 (en) | 2020-07-30 |
CN101600502A (en) | 2009-12-09 |
WO2008098947A1 (en) | 2008-08-21 |
DE102007010412A1 (en) | 2008-08-14 |
CN101600502B (en) | 2012-11-14 |
US20100059549A1 (en) | 2010-03-11 |
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Legal Events
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RIN1 | Information on inventor provided before grant (corrected) |
Inventor name: KATHE, ULRICH Inventor name: RAMIZI, MASAR Inventor name: SCHIPOLOWSKI, THOMAS Inventor name: BETTMANN, OLIVER |
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DAX | Request for extension of the european patent (deleted) | ||
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN |
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18D | Application deemed to be withdrawn |
Effective date: 20140902 |