AUTOMATED VOLUMETRIC DEVICE

Abstract

The present invention concerns the technical field of volumetric measurement and volumetric instruments and provides novel devices and methods for the determination of the volume of a fluid.

Claims

1. A volumetric device for the automated measurement of the total volume of a fluid (10) comprising: a vessel (20) for receiving the fluid (10), the vessel (20) having an open top end (21) for access to the fluid (10) and a bottom tip (22) for release of the fluid (10); a quantizing device (30), which is integrated into the bottom tip (22) of the vessel (20) for receiving all fluid (10) from the vessel (20) and quantizing all fluid (10) into a plurality of uniform partial volumes and repetitively releasing a plurality of droplets (11), each of said uniform partial volume; a detector (40) for individually detecting each droplet (11) of the plurality of droplets released from the quantizing device (30); and a counter (50) in signal-connection to the detector (40) for counting each droplet event detected; characterized in that the volumetric device further comprises: a driver head (60) attachable directly to the open top end (21) of the vessel (20) for repetitive application of individual pressure pulses onto the fluid (10) contained in the vessel (20) to each effect release of individual droplets (11), each of said uniform partial volume.

2. The volumetric device of claim 1, wherein the quantizing device (30) is a capillary valve (32) normally closed and drivable to open by individual pressure pulses applicable to the fluid (10), thereby releasing each one droplet (11) of uniform partial volume upon one or more pressure pulse applied.

3. The volumetric device of claim 1, further comprising: a holder (26) for receiving the vessel (20) containing the fluid (10).

4-5. (canceled)

6. The volumetric device of claim 1, wherein the droplet detector (40) is selected from the group consisting of: light detectors, photoelectric barriers, capacitive sensors and piezoelectric sensors and combinations of any two or three thereof.

7. The volumetric device of claim 1, further comprising: a receiver vessel (70) for receiving the plurality of droplets (11) released from the from the quantizing device (30), the receiver vessel (70) optionally being detachable from the volumetric device.

8. The volumetric device of claim 1, further comprising: a microcontroller (80), programmed to calculate the total volume of the fluid (10) from the total number of droplets (11) of partial volume of said fluid, given the predetermined partial volume of each droplet (11).

9. The volumetric device of claim 1, wherein the vessel (20) is in the form of a disposable container, selected from the group comprising reaction tubes, vials, cups and multiwell-plates, and which comprises a capillary valve (32) that is integrated into the bottom tip (22) of the vessel (20).

10. A method of volumetric measurement of the total volume of a fluid (10), comprising the steps of: a) receiving the fluid (10) to be metered in a vessel (20); b) emptying and concomitantly quantizing all of said fluid (10) from the vessel (20) repeatedly to produce and release a plurality of droplets (11) of uniform partial volume until all volume of fluid (10) is released, wherein the fluid (10) is quantized into the plurality of uniform partial volumes by means of repeated dosing steps, each dosing step yielding one quantum of said partial volume and wherein each one dosing step includes the steps of: b1) applying one or more pressure pulse to the fluid (10) and thus b2) driving a fraction of said fluid (10) through a capillary valve (32), which is integrated into the bottom tip (22) of the vessel (20), to produce one droplet (11) of said uniform partial volume; c) individually detecting and counting each of said droplets (11) released in step (b); and d) automatically calculating the total volume of the fluid (10) from the total number of all droplets (11) that have been dosed, released, detected and counted during steps (b) and (c).

11. The method of claim 10, wherein in step (b) the uniform partial volume is from 1/10,000 to 1/1,000,000 of the expected total volume of the fluid (10) to be metered.

12. The method of claim 10, wherein step (c) includes the steps of: c1) detecting the incidence of a droplet released in step (b) and counting each incidence, and c2) determining the individual speed of each droplet released in step (b); and wherein step (d) includes the steps of: d1) automatically calculating the actual individual volume of each detected droplet (11) from the individual speed of said droplet (11), and d2) automatically calculating the total volume of the fluid (10) from the total number of droplets (11) detected in step (c) and from the actual individual volumes of the droplets (11) calculated in step (d1).

13. The method of claim 10, wherein step (c) includes the steps of: c3) receiving all volume of each droplet (11) released in step (b) on a movable surface (90), c4) controlled moving of the surface (90) after each droplet (11) received so as to generate an array of stains (92), each stain preferably located at a predetermined array position on said surface (90), and c5) automatically analyzing a two-dimensional profile of light density or light transmission of said array of stains (92) to count the stains and thus to determine the total number of droplets (11) released and/or to determine the size of each stain and thus to determine the actual individual volume of the droplets (11) released.

14. A method comprising single or periodic volume calibration of a fluid dispensing metering device using the volumetric device of claim 1.

Description

[0059] In a preferred embodiment the metering method, the vessel is pre-filled with another fluid of similar physical and chemical characteristics of the fluid of interest and then the vessel is emptied by performing the dosing process until all retrievable fluid is emptied from the vessel, except for an unavoidable residual volume which may remain in the dosing system i.e. vessel and quantizing device, i.e. in particular the capillary valve. After that preceding measure any residual volume of the system is compensated and the fluid of interest is dispensed for the actual metering of its volume according to the method described herein.

[0060] FIG. 1 schematically depicts two phases of operation of the volumetric device of the present invention. In initial phase A, a fluid, i.e. liquid (10) of unknown volume is dispensed from the tip (90) of a pipette or metering device to be calibrated into the receiving vessel (20) of the device. In phase B, a driver head (60) is placed over the vessel (20) to seal the open top (21) of the vessel (20), optionally via seal (64). A microcontroller (80) controls valve (61) of the driver head (60) to temporarily and repeatedly apply pulses of increased pressure provided in pressure line (62) onto the fluid (10) received in vessel (20). At the bottom tip (22) of the vessel (20) a capillary is formed which functions as a capillary valve. The vessel (20) together with the capillary valve in the bottom tip (22) is operable as a dosing nozzle to release single droplets (11) of fluid (10) of uniform partial volume upon provision of pressure pulses through the driver head (60). A detector (40) is located immediately adjacent to the bottom tip (22) of the vessel (20) to detect each droplet (11) leaving the capillary valve. The detector (40) is connected to a counter (50) to count the number of detection events, i.e. the droplets. The counter (50), in turn, is connected to the microcontroller (80), which is programmed to calculate the actual total volume of the fluid (10) originally received in vessel (20) from the number of droplets (11).

[0061] FIG. 2 shows a schematic drawing of a section of basic parts of a specific embodiment of the volumetric device of the present invention: A driver head (60) is placed on the end of a swivel arm (66), a slidable tray or holder (26) receives a vessel (20) which comprises a capillary valve at the bottom tip (22). Adjacent to the bottom tip (22) of the vessel 20 a droplet detector (40) is located. In a separate holder, a receiver vessel (70) for receiving liquid dripping out of the vessel (20) is installed.