JPH07294391A - Dispensing device - Google Patents

Abstract

PURPOSE:To provide a dispensing device which can detect the blocking of a foreign object on suction according to the pressure fluctuation of a pressure sensor and at the same time can perform dispensing accurately without being affected by the damper effect due to the pressure sensor on discharge. CONSTITUTION:In the dispensing device where a branch part 5 is provided at a tube 3 for connecting a suction pump 2 and a probe 1 and a pressure sensor 4 is mounted to a branch line, a solenoid valve 7 is provided between the branch part 5 and the pressure sensor 4, thus opening the valve 7 on suction and monitoring pressure fluctuation and closing the solenoid valve 7 on discharge and preventing damper effect.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dispensing device used in a sample measuring device such as an automatic analyzer for biochemical automatic analysis or a blood coagulation measuring device.

[0002]

2. Description of the Related Art Conventionally, in automatic analyzers and blood coagulation measuring devices, a sample dispensing probe is inserted into a sample container containing a sample, and a predetermined amount of sample is sucked and collected through a tube to prepare another sample. The analysis is performed by injecting it into an analysis container. FIG. 2 shows a conventional dispensing device.

In the figure, S is a sample container containing a sample, 1 is a probe for aspirating the sample from the sample container, the probe 1 is supported by an arm (not shown), and the arm is moved up and down and rotated. The probe 1 can be rotated up and down. A syringe pump 2 as a suction pump is connected to the rear end of the probe 1 via a tube 3. A T-shaped tube 5 is provided in the middle of the tube 3, and a pressure sensor 4 is attached to a branch line from the T-shaped tube 5. Reference numeral 6 denotes a control unit such as the pressure sensor 4, the syringe pump 2 and the probe lifting / lowering rotation mechanism for controlling the operation of the present apparatus.

In this dispenser, first, the probe 1 is inserted into the sample container S, and the syringe pump 2 is driven to suck the sample liquid into the probe 1. At this time, the signal of the pressure sensor 4 branched and connected to the tube 3 is monitored to check if there is any pressure fluctuation. If the pressure fluctuates, it is determined that the foreign matter is clogged or the sample in the container is insufficient, and an abnormal signal to that effect is sent.

If no abnormality is determined during suction,
Subsequently, the probe 1 is moved up and down, rotated, moved into another prepared analysis container, and then the syringe pump 2 is operated to inject the sample solution therein.

[0006]

As the pressure sensor used in such a dispensing device, a piezoelectric element is generally used in consideration of various points such as pressure fluctuation range, chemical resistance and cost. . However, a characteristic of the piezoelectric element is that when a sample is sucked or ejected, a damper effect, that is, a change in capacitance due to a change in shape of the piezoelectric element in response to pressure fluctuations, is caused by this effect. ) Is a factor that deteriorates the accuracy.

The present invention has been made in order to solve such a problem, and an object of the present invention is to provide a dispensing device which does not cause a measurement error of a minute dispensing amount due to a pressure sensor.

[0008]

A dispensing device of the present invention made to solve the above problems is provided with a branch portion in a tube connecting a suction pump and a dispensing probe, and a pressure sensor is used as a branch line. In the dispensing device attached to, the electromagnetic valve is provided between the branch portion and the pressure sensor. The operation of the dispensing device of the present invention will be described below.

[0009]

In the dispensing apparatus of the present invention, when the sample is sucked, the electromagnetic valve is opened and the pressure change is detected by the pressure sensor to check whether there is an abnormality such as clogging of foreign matter or insufficient sample. After the suction is completed, the electromagnetic valve is closed, the probe is lifted from the sample container, the probe is rotationally moved to the other prepared analytical container side, and a predetermined amount is discharged therein. By doing so, highly accurate dispensing can be performed without being affected by the damper effect of the pressure sensor during ejection.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a sample dispensing apparatus in an automatic analyzer according to an embodiment of the present invention. In this figure, the same parts as those in the conventional example are designated by the same reference numerals, and the description thereof will be omitted.

This dispensing device has a pressure sensor 4 in a line branched from the tube 3 through a T-shaped tube 5 as in the conventional example, but an electromagnetic sensor is provided between the pressure sensor 4 and the T-shaped tube 5. A valve 7 is provided.

The electromagnetic valve 7 is adapted to be opened / closed by a signal from the control unit 6 which controls the operation of the apparatus.

Next, the operation of this apparatus will be described with reference to the time chart shown in FIG. A large number of sample containers are prepared in advance in the automatic analyzer, and these sample containers are sequentially sent one by one to a predetermined sample collection position of the pipetting device, and the pipetting operation is performed by the following operation.

With the probe 1 in the sample collection position, the probe 1 is lowered into the sample container S and stopped (the lowered position is a well-known method using a liquid level sensor, and the raised position is a position detection limit switch provided in the elevating mechanism). It is detected by a well-known method.

The syringe pump 2 is pulled out to suck the sample liquid in the sample container S. The amount of suction is the sum of the amount required for analysis measurement and the amount required for preventing dilution of the sample, and suction is performed a little more than the amount injected into the analysis container. At this time, the electromagnetic valve 7 is left open to monitor whether the pressure during suction changes.

If the pressure fluctuation value during suction or its integrated value is a pressure fluctuation value that exceeds the set value, which is expected to occur at the suction speed at that time, etc.,
The control unit determines that normal suction could not be performed, assuming that clogging or the like due to foreign matter contained in the liquid occurred during suction. Further, when the pressure fluctuation value is much smaller than the expected set value, the control unit determines that the normal suction cannot be performed because the liquid is insufficient during the suction.

In these cases, the control unit issues an error signal or a sample shortage signal to notify the measurer of that fact.

After the suction is completed, the electromagnetic valve 7 is closed. When the normal suction is performed, the probe 1 is then moved up, rotated to the position of the analysis container M, and then lowered to insert the probe 1 into the analysis container M.

Subsequently, the syringe pump 2 is pushed up,
A predetermined amount of liquid is discharged. At this time, since the electromagnetic valve 7 is closed, when the syringe pump is pushed in, the fluid is not in communication with the pressure sensor that produces the damper effect.
Therefore, the liquid can be discharged without being affected by the pressure sensor, and highly accurate dispensing can be performed.

After the discharge is completed, the probe 1 is raised and rotated to above the cleaning position where the cleaning container C is located. The probe 1 is lowered at that position, and the inner surface and outer surface of the probe 1 are washed with a washing liquid.

After the cleaning is completed, the electromagnetic valve 7 is opened and the probe 1 is moved up and rotated to complete one cycle of sample dispensing operation.

When dispensing the next sample, the same process is repeated from the beginning. After that, a large number of samples can be automatically analyzed by repeating this series of operations.

[0023]

As described above, in the dispensing apparatus of the present invention, the pressure fluctuation is monitored by opening the electromagnetic valve during the suction of the sample. Therefore, it is possible to accurately judge the clogging and the shortage of the sample, and to check the electromagnetic after the suction. Dispensing into the analysis container after closing the valve allows accurate dispensing without being affected by the damper effect of the pressure sensor during dispensing.

[Brief description of drawings]

FIG. 1 is a diagram showing a dispensing device according to an embodiment of the present invention.

FIG. 2 is a view showing a conventional dispensing device.

FIG. 3 is a diagram showing a time chart for explaining the operation of the dispensing apparatus according to the embodiment of the present invention.

[Explanation of symbols]

 1: Probe 2: Syringe pump 3: Tube 4: Pressure sensor 5: T-shaped tube 6: Control part 7: Electromagnetic valve S: Sample container M: Analysis container C: Washing container

Claims (1)

[Claims] 1. A dispensing device in which a branch portion is provided in a tube connecting a suction pump and a dispensing probe and a pressure sensor is attached to a branch line, and an electromagnetic valve is provided between the branch portion and the pressure sensor. Dispensing device characterized by.