Drip-resistant pipetting device and drip-resistant pipetting method

• US 7,581,660 B2
• Filed: 11/09/2005
• Issued: 09/01/2009
• Est. Priority Date: 11/09/2005
• Status: Active Grant

• Current Assignee: Hamilton Bonaduz AG (Hamilton Company)
• Original Assignee: Hamilton Bonaduz AG (Hamilton Company)
• Inventors: Bentz, Markus, Ackermann, Rene, Nay, Renato
• Primary Examiner(s): Nicolas; Frederick C.
• Application Number:
  US11/272,333
• Publication Number:
  US 20070102445A1
• Time in Patent Office: 1,392 Days
• Field of Search: 222/52, 222/61, 222/63, 222/571, 222/1, 222/386.5, 222/389, 222/394, 222/399, 222/334, 422/99, 422/100, 137/487.5, 738/640.1, 738/641.6, 738/641.8, 738/641.1, 738/630.1, 417/44.2
• US Class Current: 222/61
• CPC Class Codes: B01L 2200/0615 Loss of fluid by dripping
• CPC Class Codes: B01L 2300/14 Means for pressure control
• CPC Class Codes: B01L 2400/0487 fluid pressure, pneumatics
• CPC Class Codes: B01L 3/021 Pipettes, i.e. with only one conduit for withdrawing and redistributing liquids

Abstract

A liquid-metering device is disclosed, in particular, a pipetting device for aspirating and dispensing liquids. The device comprises a vessel which is at least partially filled with gas and has an opening through which liquid is received or discharged, a gas-pressure-changing device for changing the gas pressure in the vessel, a state-variable-detecting device for detecting at least one state variable of the gas in the vessel, and a control device which activates the gas-pressure-changing device as a function of the state variable detected by the state-variable-detecting device. The control device is a regulating device which, during a regulating time segment between liquid reception and liquid discharge, activates the gas-pressure-changing device as a function of the detected state variable such that the actual gas pressure in the vessel is kept essentially at a predetermined gas pressure.

Claims

1. A liquid-metering device for aspirating and dispensing liquids, the device comprising:

a vessel which is at least partially filled with a gas and has an opening through which a liquid is received into the vessel or is discharged therefrom, the gas, when the liquid is received, being enclosed by vessel walls and the liquid itself;

a gas-pressure-changing device for changing the gas pressure in said vessel;

a state-variable-detecting device for detecting at least one state variable of the gas in said vessel; and

a control device which activates said gas-pressure-changing device as a function of the state variable detected by said state-variable-detecting device, wherein said control device is a regulating device which, at least during a regulating time segment between liquid reception and liquid discharge, activates said gas-pressure-changing device as a function of the detected state variable in such a manner that the actual gas pressure in said vessel is kept essentially at a predetermined desired gas pressure during the regulating time segment, and further, wherein the regulating time segment comprises a time domain in a first half of a period of time lying between a final moment of a liquid-receiving operation and a moment of starting a liquid-discharging operation.

2. A liquid-metering device for aspirating and dispensing liquids, the device comprising:

a vessel which is at least partially filled, with a gas and has an opening through which a liquid is received into the vessel or is discharged therefrom, the gas, when the liquid is received, being enclosed by vessel walls and the liquid itself;

a gas-pressure-changing device for changing the gas pressure in said vessel;

a state-variable-detecting device for detecting at least one state variable of the gas in said vessel; and

a control device which activates said gas-pressure-changing device as a function of the state variable detected by said state-variable-detecting device, wherein said control device is a regulating device which, at least during a regulating time segment between liquid reception and liquid discharge, activates said gas-pressure-changing device as a function of the detected state variable in such a manner that the actual gas pressure in said vessel is kept essentially at a predetermined desired gas pressure during the regulating time segment, and further, wherein the regulating time segment comprises a first quarter of a period of time lying between a final moment of a liquid-receiving operation and a moment of starting a liquid-discharging operation.

3. A method for avoiding losses of drops in a liquid-metering device, comprising the following steps which are carried out at least in one time segment between a liquid-receiving operation and a liquid-discharging operation:

detecting at least one state variable of a gas, which is substantially enclosed between vessel walls of a vessel of a liquid-metering device and a liquid received in the vessel; and

regulating a pressure of the gas as a function of a state variable detected in such a manner that as actual gas pressure substantially corresponds with a predetermined desired gas pressure, wherein said detecting step and said regulating step take place during a regulating time segment which comprises a time domain in a first half of a period of time lying between a final moment of a liquid-receiving operation and a moment of starting a liquid-discharging operation.