JPS5841094B2 - Liquid metering and feeding device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid metering and supplying device used in blood analyzers and the like.

In order to accurately analyze a small amount of liquid in a blood analyzer or the like, it is necessary to meter and supply liquid as a specimen or reagent with high precision.

Conventional methods for measuring and supplying small amounts of liquid include (a) using instruments such as pipettes, (b) using instruments such as syringes, and (c) supplying a fixed amount of gas into a container containing liquid. However, there are other methods such as pushing out the liquid.

However, methods (a) and (b) require the operation of suctioning and metering the liquid once for each supply, which is inconvenient for repeated metering and supply.

Furthermore, droplets are likely to form at the supply port due to the viscosity and surface tension of the liquid, making it difficult to equalize the desired measured value and the actual supply amount value.

Additionally, there are limits to the mechanical dimensional accuracy of syringes and the like.

Compared to methods (a) and (b), method (c) has the advantage that it does not require inhalation of liquid each time it is supplied, but like methods (a) and (b), droplets are formed at the supply port. In addition, since gas is used, there are limits to errors due to the shrinkage of the gas due to pressure, and the accuracy of devices such as pumps that stably and reliably feed a small amount of gas. There were many drawbacks such as variations in the amount of liquid supplied.

The present invention was made with the aim of achieving unprecedented high-precision metering and supply by utilizing the phenomenon in which uniform minute liquid droplets are ejected by driving an electrostrictive element. An electrostrictive element is attached near the open end of the thin tube connected to the
The present invention provides a liquid metering and supplying device characterized in that the electrostrictive element is driven and controlled to divide and discharge liquid into a plurality of minute droplets and meter and supply the liquid.

Embodiments of the present invention will be described in detail with reference to the drawings.

In FIG. 1, 1 is a liquid container, and 2 thin tubes are connected to it.

The liquid in the container 1 fills the thin tube 2 due to capillarity,
When the local cross-sectional area of the capillary tube 2 is rapidly narrowed using the method described above, the liquid within the capillary tube 2 becomes minute droplets and is discharged from the open end, that is, the free end of the capillary tube 2.

As a means for rapidly narrowing the local cross-sectional area of the thin tube 2, an electrostrictive element is used.

As the electrostrictive element 3, lead zirconate titanate-based porcelain or the like exhibits an electrostrictive effect with good conversion efficiency, and is known for not only having stable characteristics at general operating temperatures but also having little change over time. .

The electrostrictive element 3 is capable of ejecting a uniform group of minute liquid particles with high precision, high speed, and stability using an electric signal.

In this case, by using the means known in Japanese Patent Publication No. 54-35936 and the like, it is possible to prevent droplets from forming at the opening, that is, the supply port, and therefore high accuracy can be maintained in metering and supply.

Here, the liquid metering and supplying device using the above-mentioned micro droplet discharging section will be explained in order of operation.

The weight of each minute droplet to be ejected varies depending on the type of liquid, so if it is known in advance, that value is entered into the operating section 4.

When supplying an unknown liquid or making a new correction, the program of the control unit 5 causes Co liquid droplets to be released.

To eject Co liquid droplets, the number of drive pulses by the signal generator 6 is limited to C8 by the gate 7, and the drive unit 8 performs waveform shaping to drive the electrostrictive element 3.

Co liquid droplets are collected in an analysis (reaction) container 9, and the weight of the obtained liquid volume is A.

Weigh with a weighing scale 10. The measured value from the weight scale 10 is input to the control section 5.

The control unit 5 calculates and stores the weight B per droplet by calculation (B=AO/CO).

Now, when the liquid amount A is input and requested to the operation unit 4, the control unit 5 calculates the number of liquid droplets C (C=A/B), and this value is preset in the counting circuit in the control unit 5, and the liquid Metered supply starts.

The gate 7 is opened and a signal is sent to drive the electrostrictive element 3.

- The force control unit 5 counts down the number of drive pulse signals from the preset value, and when it reaches O, closes the gate 7 and finishes supplying the liquid droplets.

In the above, the weight B per droplet was calculated as a preparatory step, and then the weight B was measured and fed, but in practice, the weight B of the liquid droplet was calculated while metering and feeding, and the liquid amount A was then metered and fed. It is also possible to do so.

In the present invention, since it is electrically controlled as described above, by changing the amount of drive pulses generated per unit time from the signal generator 6, it is possible to control the amount of liquid supplied per hour very precisely. can.

In addition, in the above embodiment, by adding a conveyance system such as a container that receives liquid supply and synchronizing the operation of the conveyance system with the metered supply of the present invention, it is possible to automatically perform metered supply multiple times. becomes.

In addition, by installing a weight scale in the above-mentioned conveyance system and adding a mechanism and program that automatically calculates and calibrates the relationship between the supplied liquid weight value and the supplied liquid droplet count, it is possible to handle liquids with different properties. It is also possible to change the metering automatically.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention. 1... Container, 2... Thin tube, 3...
...Electrostrictive element, 4...Operation unit, 5...
Control unit, 6... Signal generation unit, 7... Gate, 8... Drive unit, 9... Analysis (reaction) container, 10... ...Weight scale, 11...
Display section.

Claims (1)

[Claims] 1. An electrostrictive element is installed near the opening end of a thin tube connected to a liquid container, and the electrostrictive element is driven and controlled to divide and discharge the liquid into a plurality of micro droplets and calculate the number of micro droplets;
A liquid metering and supplying device in which the electrostrictive element is controlled and operated.