JPH0222680Y2 - - Google Patents

Description

[Detailed explanation of the idea]

[Industrial Application Field] This invention relates to a dispensing device for dispensing a specimen sample from a sample container and injecting it into a reaction tube in an automatic biochemical analyzer or the like, and in particular to an improvement of its dispensing nozzle. [Prior Art] A dispensing device used in an automatic biochemical analyzer etc. has a dispensing nozzle that aspirates a sample contained in a sample container and discharges the sample into a reaction tube. A moving mechanism that moves the nozzle between the sample container, reaction tube, and nozzle cleaning/drainage tank, aspirates and discharges the sample using the dispensing nozzle, and aspirates and sends out pure water for cleaning the dispensing nozzle. It consists of a syringe pump, a dispensing nozzle, a switching valve that switches the flow path between the pure water container and the syringe pump, and each piping tube. When performing a dispensing operation using a dispensing device having such a configuration, each pipe is filled with pure water.
The suction and discharge of the sample is performed in the piping tube that connects the dispensing nozzle and the switching valve.The dispensing nozzle is cleaned after suctioning and dispensing one sample with pure water from the deionized water container using the syringe pump. After suctioning, the flow path is switched using a switching valve, and pure water is discharged from the nozzle tip into the cleaning/draining tank through the piping tube and the inside of the dispensing nozzle. By the way, conventional dispensing nozzles are
It is made from a straight stainless steel tube, and the tip is narrowed to make it easier to drain the liquid. [Problems that the invention aims to solve] In general, the smaller the inner diameter of a dispensing nozzle, the greater the flow resistance and the longer time it takes to transfer the liquid, and the smaller the inner diameter of the dispensing nozzle, the larger the inner diameter. When the sample is inhaled, the area of the inner wall of the tube that comes into contact with the sample increases, and therefore the sample tends to be diluted by the pure water adhering to the inner wall surface of the tube. However, if the inner diameter of the dispensing nozzle is small, the flow state of the liquid flowing inside it tends to be turbulent, and even if it becomes laminar flow, the difference in flow velocity between the center of the flow and the vicinity of the inner wall of the pipe is small. In any case, the advantages are that it is relatively easy to clean the sample adhering to the inner wall surface of the dispensing nozzle, and the amount of cleaning water is small. On the other hand, if the inner diameter of the dispensing nozzle is large, the flow path resistance is small, so it does not take much time to transfer the liquid, and the area of the inner wall that the sample comes into contact with is relatively small, resulting in pure water adhering to the inner wall of the tube. The dilution of the sample due to However, if the inner diameter of the dispensing nozzle becomes larger, the flow state of the liquid flowing inside the pipe becomes laminar, and the flow velocity near the inner wall of the pipe becomes slower than at the center of the flow, and the speed at which the cleaning water is sent out is limited. Even if the flow rate is increased, the flow velocity near the inner wall surface of the tube does not increase much, so it is difficult to clean the sample adhering to the inner wall surface of the dispensing nozzle, and there are disadvantages in that a large amount of washing water is required. As described above, conventional dispensing nozzles have advantages and disadvantages depending on their inner diameter. Therefore, this invention was made in an attempt to provide a dispensing nozzle that combines the advantages of each of these and has a high degree of cleaning even if the cross-sectional area of the flow path is large. [Means for solving the problem] This invention achieves the above-mentioned problems by deforming a straight pipe into a flattened shape at appropriate points, or by deforming a straight pipe into a meandering shape to construct a dispensing nozzle. . [Function] The dispensing nozzle according to this invention is not simply a straight tube, but has an uneven inner wall surface, or an irregular cross-sectional shape.
The flow state of the liquid flowing through the internal flow path remains turbulent even if the cross-sectional area of the flow path of the dispensing nozzle is increased.
In that case, since the flow passage cross-sectional area of the dispensing nozzle is large, the flow passage resistance does not become so large as long as the inner wall surface is smooth. [Example] Hereinafter, an example of this invention will be described with reference to the drawings. First, the schematic configuration of the dispensing device will be explained based on FIG. 4. In the figure, the dispensing nozzle 11 is reciprocated between the positions of the sample container 15, the reaction tube 17, and the nozzle cleaning/draining tank 19 by a dispensing nozzle moving device 13. Furthermore, the dispensing nozzle 11
is movable in the vertical direction, and sucks and separates the sample contained therein at the position of the sample container 15, moves to the position of the reaction tube 17, and discharges the collected sample into the reaction tube 17. inject. Further, the dispensing nozzle 11 is connected to the inner wall surface of the dispensing nozzle 11 and the piping tube 21 by pure water sent through the inside of the piping tube 21 at the position of the nozzle cleaning/drainage tank 19.
The sample adhering to the inner wall surface near the connection part with the dispensing nozzle 11 is washed away, and the drained liquid is discharged.
The piping tube 21 is made of a flexible, chemical-resistant material, such as a Teflon tube. Further, pure water is sent by the syringe pump 23, which is connected to the piping tube 2.
1 to the dispensing nozzle 11, and also to a pure water container 27 via a pure water suction tube 25. Then, flow path switching between the syringe pump 23, the dispensing nozzle 11, and the pure water container 27 is performed by a switching valve 29 such as a solenoid valve. As described above, during the dispensing operation, the piping tube 21 and the pure water suction tube 25 are filled with pure water, and the sample is sucked and discharged by the dispensing nozzle 11 and a part of the piping tube 21. In addition, when cleaning the sample adhering to the inner wall surface of the dispensing nozzle 11 and a part of the inner wall surface of the piping tube 21, after sucking pure water from the pure water container 27 via the pure water suction tube using the syringe pump 23, , switching valve 2
9 switches the flow path, and the syringe pump 23
This is performed by sending pure water to the dispensing nozzle 11 side and discharging the pure water from the dispensing nozzle 11. Next, the dispensing nozzle according to this invention will be explained. Fig. 1-1 is a longitudinal sectional view of a dispensing nozzle showing one embodiment of this invention, and Fig. 1-2 shows only each end face and each cross-section of the dispensing nozzle when viewed in the direction of the arrow. FIG. The dispensing nozzle 31 is made of stainless steel pipe (for example, outer diameter 1.5 mm, inner diameter
1.0mm). The tip is narrowly squeezed to allow for better liquid drainage. In the middle of the pipe, the pipe is flattened at multiple locations by sequentially changing the major diameter direction by 90 degrees, and the cross-sectional shape at each location becomes elliptical. To give an example of the dimensions of the elliptical cross section, the major axis is 1.8 mm and the minor axis is 1.0 mm at the outer periphery. Here, the inner surface of the pipe is uneven, but it is finished smoothly to avoid any angular parts. The flat portion may be formed by, for example, holding a straight pipe between a pair of jigs and sandwiching the pipe with an appropriate force between the jigs. When this dispensing nozzle 31 is attached to a dispensing device and dispensing operation is performed, when pure water is flowed inside the dispensing nozzle 31 to clean it, the inner wall surface is uneven and the Since the cross section is not circular but elliptical, the pure water flows in a turbulent state within the dispensing nozzle 31 and is discharged from the tip of the dispensing nozzle 31. The following table shows the results of a comparative experiment between a dispensing device equipped with this dispensing nozzle 31 and a dispensing device equipped with a conventional straight pipe dispensing nozzle (two types, thick and narrow). . The values in parentheses in the table are as follows: After aspirating and discharging 340 μl of phosphoric acid aqueous solution (sample) through the dispensing nozzle, use 900 μl of pure water to clean the inner wall surface of the piping tube and dispensing nozzle. After washing, 340 μl of pure water was sucked and discharged through a dispensing nozzle, and the concentration of phosphorus in the discharged liquid was measured.Actually measured values are shown.

〔effect〕

This invention is constructed and operates as described above. According to the dispensing nozzle according to this invention, the cross-sectional area of the flow path can be increased, so the flow path resistance is reduced, and the dispensing nozzle according to the invention is The nozzle can aspirate and discharge the sample as well as send out the cleaning water in a relatively short time. In addition, when the sample is inhaled, the area of the inner wall of the tube that comes into contact with the sample becomes relatively small, which reduces the dilution of the sample caused by pure water adhering to the inner wall of the tube, thereby preventing a drop in dispensing accuracy. Can be done. Even if the cross-sectional area of the flow path is increased, a turbulent flow occurs when the liquid flows inside the dispensing nozzle, so the degree of cleaning is high and the amount of cleaning water is small. Another advantage is that the molding process is easy.

[Brief explanation of the drawing]

1-1 and 1-2 show one embodiment of this invention, FIG. 1-1 is a longitudinal sectional view of the dispensing nozzle, and FIG. 1-2 is a first embodiment of the dispensing nozzle.
2-1 and 2-2 show another embodiment of this invention, respectively, as viewed in the direction of the arrow in FIG. 1. 1
The figure shown in the same way as Figures 1-2, and Figure 3 are as follows:
FIG. 7 is a longitudinal cross-sectional view of a dispensing nozzle that is still another embodiment of this invention. Moreover, FIG. 4 is a diagram for explaining the schematic configuration of the dispensing device. 11, 31, 31', 31''...dispensing nozzle, 1
3...Dispensing nozzle moving device, 15...Sample container,
17...Reaction tube.

Claims (1)

[Scope of utility model registration request] In a dispensing nozzle that is movable between the positions of a sample container, a reaction tube, and a cleaning tank, and that sucks and separates a sample contained in a sample container and discharges and injects the sample into a reaction tube, A dispensing device characterized by having a portion deformed into a flattened portion or a straight pipe deformed into a meandering shape.