초록 ▼

The invention relates to a method and equipment for quantitatively dosing small amounts of liquid, especially in clinical or other similar wet-chemical analyzers. The dosing employs a liquid space, the volume of which can be changed and which is connected to a dosing channel so that, by increasing o

The invention relates to a method and equipment for quantitatively dosing small amounts of liquid, especially in clinical or other similar wet-chemical analyzers. The dosing employs a liquid space, the volume of which can be changed and which is connected to a dosing channel so that, by increasing or decreasing the volume of the liquid space, a suction or an injection through the dosing channel is achieved. The liquid space is formed by flexible bellows which are freely movable back and forth to provide the reversible deformations which change the volume of the liquid space. The movements are effected using an actuator which is connected to the bellows without transmissions containing sliding surfaces. The actuator comprises precisely repeatable positions and is calibrated according to the invention by measuring the sizes of the dosages produced by the movements between the positions. The dosing is effected after that by selectively repealing the calibrated movements. The actuator can be formed by a stepper motor, and a cam shaft rotated by the stepper motor propelling the bellows back and forth. The nonlinear interdependent relationship between the rotation of the shaft and the change in the volume of the liquid space makes possible a wide range of calibrated dosage sizes.

대표청구항 ▼

A method for quantitative precision dosing of small amounts of liquid by use of a liquid space defined by a flexible bellows which is connected to a dosing channel, said bellows being adapted to move freely back and forth by means of an actuator having a range of precisely repeatable positions, move

A method for quantitative precision dosing of small amounts of liquid by use of a liquid space defined by a flexible bellows which is connected to a dosing channel, said bellows being adapted to move freely back and forth by means of an actuator having a range of precisely repeatable positions, movements of the actuator between said positions being transmitted to the bellows through a transmission mechanism without sliding movement in said transmission mechanism, the method comprising the steps of: calibrating the actuator by driving the actuator through a number of said positions, each driving movement of the actuator between two selective positions of said positions, producing a reversible change in a volume of the liquid space and a transfer of a corresponding volume of liquid by suction or injection through said dosing channel, and measuring said transferred amounts so as to establish a range of calibrated doses of liquid; and performing dosing by selecting a calibrated dose of liquid and driving the actuator between the two selected positions used for the calibration of the selected dose, the movement of the actuator being transmitted to the bellows to produce a change of the volume of the liquid space and suction or injection of an amount of liquid forming the dosed amount corresponding to said selected dose. An equipment for quantitative precision dosing of small amounts of liquid selected from a range of predetermined liquid doses, the equipment comprising: a liquid space limited by flexible bellows, said flexible bellows having a range of repeatable bellows positions corresponding to different volumes of said liquid space and being freely movable back and forth to enable reversible movements between said bellows positions, the liquid space volume changes produced by said movements defining said range of liquid doses, and said liquid space communicating with a dosing channel so that selective movements of the bellows together with a thereby increased or decreased volume of the liquid space produce selective doses from said range of liquid doses by means of suction or injection of liquid through the dosing channel; and an actuator which is, without transmissions containing sliding surfaces, connected to the bellows for moving the bellows, the actuator comprising a range of positions which can be precisely repeated for bringing the bellows into said repeatable bellows positions, the dosing being effected by selective steps of the actuator between said actuator positions causing the bellows to be moved between the corresponding bellows positions and a dose of liquid to be sucked or injected.