JP2007322148A - Dispensing pipe and analyzer using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the point at issue that a dispensing pipe used in a dispenser for transferring a liquid to another container causes a liquid to remain and the contamination between a different kind of chemical reaction reagents to occur in the next suction process of a reaction container when a residual liquid is sucked in a suction/discharge container after the reagents are sucked in the reaction container and raises the fear of bringing about abnormality in a measuring result. <P>SOLUTION: The dispensing pipe, which performs at least either one of the suction and discharge of a liquid is equipped with a straight pipe part arranged so as to become narrow parallelly and stepwise in its inner diameter along the center axis line regulating the surface roughness ratio of its inner surface and the contracted diameter part for joining the straight pipe part. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a dispensing tube for sucking a liquid and an analyzer using the same in order to transfer the liquid to another container, and particularly to a dispensing mechanism of a clinical automatic analyzer requiring high dispensing accuracy. The present invention relates to a suitable dispensing tube and analyzer.

  In recent years, automatic analyzers that qualitatively and quantitatively analyze biological samples such as blood and urine have been widely used mainly in large hospitals and examination centers because of their high throughput and measurement reproducibility.

  The principle of the automatic analyzer is to measure a color change as absorbance with a photometer using a reagent that changes color by reacting with a specific component in a sample.

  One of the needs for automatic analyzers is to reduce the amount of reagents used in order to reduce running costs. A reduction in the amount of sample to be aspirated is also required in accordance with the reduction in the amount of reagent.

  In the current automatic analyzer, the amount of sample is on the order of 1 to 2 digits of microliter, but providing a dispensing mechanism for accurately dispensing such a small amount of liquid requires advanced technology.

  In addition, the dispensing mechanism is required to dispense a predetermined amount of different samples, but if the amount of sample to be dispensed is small, the sample will be mixed if another sample is not dispensed after sufficient washing. Later analysis results may be adversely affected.

  For this reason, a dispensing probe with high dispensing accuracy and good cleaning properties is desired.

  Patent Document 1 discloses a dispensing probe having a shape in which the inner diameter is gradually reduced so as to improve the cleaning performance.

JP 2005-249535 A

  In the technique described in Patent Document 1, turbulent flow is generated by the specific shape of the pipette pipette to improve the cleaning performance.

  However, even if it is turbulent flow, it is a flow that has a direction toward the tip of the dispensing nozzle, and depending on the unique shape, a place where the attached sample tends to fall and a place where the attached sample tends to remain are formed. As a result, a great effect cannot be obtained.

  On the other hand, in the shape in which turbulent flow is likely to occur, the flow at the time of suction is also non-uniform, and it is difficult to obtain sufficient dispensing accuracy by generating bubbles and entraining them inside.

  In view of the circumstances described above, an object of the present invention is to provide a dispensing tube having good cleaning properties without affecting the dispensing accuracy.

  In order to achieve the above object, according to the present invention, in a pipe for performing at least one of liquid suction and discharge, a straight pipe portion disposed so that the central axis is parallel and the inner diameter is narrowed; The reduced diameter part provided between the straight pipe parts was provided, and the surface roughness ratio of the inner surface of the straight pipe part and the inner surface of the reduced diameter part was set to 1: 5 to 1: 7.

  Although there are several methods for evaluating the surface roughness, the arithmetic average surface roughness Ra is used.

  Since the contamination of the reagent / cleaning liquid is minimized, the measurement accuracy of the analyzer is improved.

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

  FIG. 1 is a conceptual diagram showing the present invention.

  An outline of the structure of the dispensing pipe 1 is as follows. The dispensing tube 1 has an inner diameter difference between the straight tube portion distal end portion 2 and the straight tube portion thick portion 4 and is connected by the reduced diameter portion 3 therebetween.

  Here, since the reduced diameter portion 3 is a specific portion of the dispensing tube 1, when a predetermined amount of liquid is dispensed, it becomes a portion where the liquid is more likely to adhere than the straight tube portion 2.

  However, during cleaning, the pressure of the cleaning liquid increases in the reduced diameter portion, and the inner diameter becomes narrower on the terminal side of the reduced diameter portion (the distal end side of the dispensing tube), so the flow rate increases. Thereby, when the sample 5 is sucked and discharged, the sample 6 accumulated in the reduced diameter portion is scraped out.

  Therefore, by providing the reduced diameter portion and the straight tube portion, a dispensing tube with high cleaning properties can be obtained.

  On the other hand, in order to generate turbulence, it is not effective to make the entire surface of the flow path as a mirror surface with a uniform surface roughness as well as the shape. It is also useful to configure with this.

  Establishing technology to finely process the average roughness of pipes composed of straight lines down to 0.01μm by using various mechanical and chemical processing methods for the average inner surface roughness of metal pipes such as stainless steel pipes. Has been.

  However, in the case where the accuracy of discharging and sucking liquid is required in the pressure range that can be used in the analyzer with respect to the usage amount region required by the analyzer, it is difficult to form a dispensing tube with only a straight portion.

  In addition, if the dispensing tube is simply a thin tube, the flow rate is increased, but turbulent flow is not always generated.

  Therefore, in order to construct a dispensing tube having a high cost efficiency and a high cleaning efficiency, it is ideal to increase the flow rate of the inner tube of the sample and at the same time create a turbulent flow region of the liquid.

  For this purpose, the dispensing tube has a straight pipe part and a slanted pipe part with a narrower straight part and a slanted part that is added to the part where the sample is aspirated or discharged. A stepwise difference in inner diameter was required.

  The present invention has focused on defining the surface average roughness of the inner surface based on the background art.

  If it is limited to a straight pipe part by a conventional technique, the processing of the inner surface and the management of the surface roughness can be realized without any problems.

  For example, (1) mechanical finishing with a mandrel (2) friction processing finishing by applying an abrasive to the outer surface of a rod shape or string shape can be mentioned. Since the methods (1) and (2) cannot be applied to the inclined portion, there are cases where chemical means (3) applying a coating agent is applied as a technical matter different from mechanical.

  In order to create an inclined portion, machining called drawing is generally performed in terms of cost. If the narrow tube whose inner surface is finished in a mirror surface is further subjected to a drawing process on the tip, the surface roughness of the inclined portion is theoretically the same as that of the straight tube.

  However, the unevenness generated during the drawing process causes distortion on the inner surface if the outer surface is finished cleanly, and it is quite difficult in principle to avoid this, and the quality cannot be aligned.

  Even if the drawing conditions are constant, it is extremely difficult to numerically manage the surface roughness and the waviness in units of μm due to the strain of the material and the processing strain at the time of processing.

  Therefore, conventionally, there has been no method capable of managing the average roughness in the pipe on the inner surface of the inclined portion in both cases (1), (2) and other cases. The average roughness value of the inner surface is shown below. This value is not subjected to the microblasting described above.

1-a: Average roughness value of the inner surface of the front end portion of the straight pipe portion 1-b: Average roughness value of the inner surface of the reduced diameter portion 1-c: Average roughness value of the inner surface of the thick portion of the straight pipe portion For example, the material surface roughness is average The surface roughness is around 0.5 μm. The processing method collectively referred to as microblast described above allows fine particles to enter the inside of the narrow tube, and smoothes irregularities not only in the diameter portion but also in the inclined portion, thereby solving various problems of the prior art.

  In this case, there are many advantages if the roughness is defined at a certain ratio in contrast to finishing the entire surface to an ideal mirror surface.

  Microblasting is not a processing method that is good at flattening surface waviness in mm units.

  The slanted portion cannot avoid the occurrence of unevenness and waviness during drawing, and large waviness remains. However, it satisfies the optimal cost and is good at smoothing finer units of μm and nm, and it is easy to generate turbulence by changing the average surface roughness at the inclined part in the middle of the flow path. Can be realized.

  The average roughness value of the inner surface in this example is shown below.

  This value was subjected to the microblasting described above. If an example of the surface roughness after processing is shown, the values are 1-aa, 1-bb, and 1-cc.

1-aa: Average roughness value of the inner surface of the straight tube portion tip portion 1-bb: Average roughness value of the inner surface of the reduced diameter portion 1-cc: Average roughness value of the inner surface of the thick portion of the straight tube portion Further, examples of the present invention It is preferable that the surface roughness ratio of the inner surface of the straight tube portion and the inner surface of the reduced diameter portion is 1: 5 to 1: 7.

  In the dispensing tube of the embodiment of the present invention, it is preferable that the reduction ratio of the inner diameter on one end side and the inner diameter on the other end side of the reduced diameter portion is 35% to 50%.

  According to the embodiment of the present invention, by appropriately setting the inclination angle of the reduced diameter portion and the inner diameter dimension of the reduced diameter portion, it is possible to obtain a dispensing tube with further improved cleaning performance.

  FIG. 2 is a conceptual diagram showing the present invention, and is a conceptual diagram showing the concept of data.

  The (1) dispensing accuracy generally has a tendency that the smaller the suction amount, the larger the amount of liquid remaining after washing, and the more effective the smaller the dispensing amount.

  For example, when a threshold value 7 (for example, CV1% expressed statistically) is set, CV value 8 when dispensing volume is 1 μl, CV value 9 when dispensing volume is 2 μl, CV value when dispensing volume is 5 μl 10. The threshold value 7 is satisfied even at a CV value of 11 when the dispensing amount is 10 μl.

  The effect of the embodiment of the present invention is remarkable, and when applied, the dispensing accuracy is reduced to a fraction, and particularly when the amount is small, the data appears remarkably and the threshold value is satisfied. Dispensing pipes that do not satisfy the threshold and can be replaced have various causes, but one is that the slope of the inclined portion is often too rough.

  According to the present embodiment, there are the following other effects.

  There are many parts manufacturing, assembly, adjustment, and processes until the performance evaluation can be performed on the analyzer. In the meantime, the parts require special care for cleaning (excluding oil) and storage (protecting oil and dust).

  And as the dispensing volume decreases, it is important to eliminate external factors such as oil and dust adhering to the parts in all steps as the amount of dispensing decreases.

  If it is limited to the operating pressure range of the analyzer, accuracy cannot be ensured when the amount of the sample 5 is reduced unless all these external factors are eliminated.

  On the other hand, it is known that surface roughness and wettability influence as technical problems.

  If this processing is performed, the dispensing tube performs an effective degreasing operation on oil and dust in the final step of the processing, so that special attention required for the cleaning and storage becomes unnecessary.

  At the same time, the total cost reduction from such time saving is a substantial effect produced by this embodiment.

  In addition, from the customer's service aspect, the surface roughness of the inner surface of the part is reduced, so that the liquid adheres less to the wall surface, and maintenance is improved over a long period of time. As a result, the quality can be stabilized.

  Strictly speaking, the remaining amount of the sample 5 remaining inside is not zero, but there is no practical influence on the analysis performance as long as the threshold value is satisfied.

  According to this embodiment, the effect of preventing the sample adhesion can be obtained, and the flow resistance of the cleaning liquid is improved due to the decrease / increase / decrease in the channel resistance, and the effect of removing the sample adhered due to the generation of the turbulent flow is also enhanced. .

  As a result, the remaining amount of the sample after cleaning can be reduced to a fraction or less.

  The difference from the prior art has been described with reference to the drawings and the data outline.

  The embodiment of the present invention has the following effects.

  (1) Dispensing accuracy is improved. (2) Time until operation of the apparatus can be shortened.

  As other effects, the total cost can be reduced, the maintainability is improved, and the quality can be stabilized.

  The above-mentioned (1) is mentioned as a particularly remarkable effect peculiar to the present embodiment for the above-mentioned reason.

  FIG. 3 is a schematic view showing the present embodiment.

  A schematic diagram of the dispensing function of this embodiment is shown in FIG. A dispensing tube 1 for aspirating and discharging a sample is provided.

  The dispensing tube 1 is supported via an arm with respect to a structure disposed coaxially with the Z-θ drive unit. The dispensing tube 1 can be moved in the height direction (Z-axis direction) and the rotation direction (θ direction) by driving the Z-θ drive unit.

  The automatic analyzer according to the present embodiment will be described in a simplified manner by omitting an explanation number. For example, a reaction disk, a sample turntable, a reagent turntable, a sample dispensing unit (dispensing device), A reagent dispensing unit (dispensing device) and the like are arranged.

  A plurality of reaction vessels are annularly arranged on the reaction disk along a concentric circumference.

  On the sample turntable, a plurality of sample containers are annularly arranged along a concentric circle.

  On the reagent turntable, a plurality of reagent bottles are annularly arranged along a concentric circumference.

  Each sample container contains a sample to be analyzed, that is, blood, urine, fecal lysate, cultured cell solution, and the like.

  Each reagent bottle individually stores a plurality of types of reagents necessary for analysis items.

  Each of the reaction disk, the sample turntable, and the reagent turntable is rotated intermittently by a rotation mechanism and can be positioned at a predetermined position.

  In the reaction disk, a sample dispensing position, a reagent dispensing position, a stirring position, a measurement position, and a reaction container washing position are set, and the positions are stored and controlled by the apparatus controller.

  The same applies to the sample turntable and the reagent turntable. The dispensing mechanism is constituted by a tube 12 and a tube holding agent 16 constituting the dispensing tube 1.

  This has the function of holding the dispensing tube simultaneously with the function of an electrostatic sensor or the like. These are constituted by a pipe motor rotating vertical shaft 13 and driven by a control motor 15. These are connected by piping wiring 14.

  The dispensing tube 1 of the sample dispensing mechanism is moved to the sample aspirating position, and is further inserted into the sample container at this position by lowering the dispensing tube.

  When the tip is lowered to a position several mm below the liquid level of the sample in the sample container, the operation of the dispensing tube is stopped, and then the syringe pump (not shown) is operated to suck the sample.

  When a predetermined amount of suction is completed, the dispensing tube is pulled up to a height that does not mechanically interfere with the sample container, and then moved to the sample dispensing position.

  After the movement is completed, the dispensing tube is lowered into the reaction container installed at the sample dispensing position, and a predetermined amount of sample is dispensed by the operation of the syringe pump.

  After the completion of the dispensing, the dispensing tube is pulled up to a position where it does not interfere with the reaction vessel and moved onto the specimen cleaning tank. When the position on the washing tank is reached, the syringe pump operates to send the washing liquid to the dispensing tube. As a result, the remaining specimen in the dispensing tube is poured out and the tip of the dispensing tube is washed.

  Thus, the dispensing of the sample into one reaction container is completed.

  The effect of the present embodiment is the same as described above.

  The technical scope of the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

The structure conceptual diagram which shows the 1st Example of this invention, and the conceptual diagram of an average roughness measured value. The dispensed quantity reproducibility data conceptual diagram which shows the 1st Example of this invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a conceptual diagram of an automatic analyzer dispensing pipe according to a first embodiment of the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Dispensing tube, 2 ... Straight pipe part front-end | tip part, 3 ... Reduced diameter part, 4 ... Straight pipe part thick part, 5 ... Sample, 6 ... Sample remaining on a wall surface, 7 ... Threshold value, 8 ... Dispensing amount 1 microliter CV value when the dispensing volume is 2 μl, 10 CV value when the dispensing volume is 5 μl, 11 CV value when the dispensing volume is 10 μl, 12... Pipe, 13. Rotating vertical axis, 14 ... wiring / piping, 15 ... control motor, 16 ... tube holding material 35, 1-a ... average roughness value of the inner surface of the straight pipe end, 1-b ... average roughness of the inner surface of the reduced diameter portion 1-c: average roughness value of the straight pipe portion thick portion inner surface, 1-aa: average roughness value of the straight tube portion tip inner surface, 1-bb: average roughness value of the inner surface of the reduced diameter portion, 1- cc: Average roughness value of the inner surface of the thick section of the straight pipe section

Claims (4)

In a dispensing tube that performs at least one of liquid suction and discharge,
A plurality of straight pipe portions having different inner diameters and a reduced diameter portion connecting the plurality of straight pipe portions having different inner diameters, and the surface roughness ratio of the inner surface of the straight pipe portion and the inner surface of the reduced diameter portion is 1: A dispensing tube characterized by being in the range of 5 to 1: 7. The dispensing tube according to claim 1,
The average surface roughness of the inner peripheral surface of the reduced diameter portion is 0.01 μm to 0.02 μm, and the average surface roughness of the inner diameter of the straight pipe portion is 0.05 μm to 0.1 μm. Dispensing tube. The dispensing tube according to claim 1 or 2,
A dispensing tube, wherein a shrinkage ratio between an inner diameter at one end and an inner diameter at the other end of the reduced diameter portion is 35% to 50%. In an analyzer comprising a reaction container into which a specimen and a reagent are dispensed, and an analysis means for examining the specimen from a mixed solution of the specimen and the reagent mixed in the reaction container,
An analyzer comprising the dispensing tube according to claim 1 as dispensing means for dispensing the sample and the reagent into the reaction container.

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