JPH08146011A - Automatic chemical analyser - Google Patents

Abstract

PURPOSE: To provide an automatic chemical analyser capable of accurately monitoring the residual amt. of a reagent in real time while reducing the load on an operator. CONSTITUTION: A liquid reagent is dispensed to a reaction container from a liquid container in which the liquid reagent is housed through a reagent dispensing tube 7. The residual amt. of the liquid reagent is monitored on the basis of the change of electrostatic capacity corresponding to the liquid level of the liquid reagent detected by the sensor part SEa inserted in the container. The sensor part SEa is equipped with a pair of electrodes (8a1, 8a2) with required length for detecting electrostatic capacity and the electrode support 9a supporting a pair of the electrode (8a1, 8a2) within the liquid container in a depth direction and formed into a liquidtight structure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discrete-type automatic chemical analyzer for multi-item, multi-specimen for simultaneously analyzing a plurality of types of items, and in particular, it has means for monitoring the remaining amount of each reagent. The present invention relates to an automatic chemical analyzer.

[0002]

2. Description of the Related Art In a discrete type multi-item, multi-specimen automatic chemical analyzer for simultaneously analyzing a plurality of types of items,
A dispensing type reagent dispensing system in which a certain amount of reagent is discharged from each reagent container to a reaction container via a dedicated reagent line is generally used.

In this type of analyzer, usually two types of reagents are often used to analyze one item. For example, in the case of analysis of 20 items, generally 40 kinds of reagents are required. The amount of reagent required for one analysis differs depending on each item, and the measurement items required for each sample also differ, so the consumption amount of each reagent is not uniform, so it is not necessary to replace all reagents at the same time. However, if careless, it may cause the reagent to run out in the middle of the analysis, and controlling the consumption of the reagent is a serious problem.

As a method for managing the reagent consumption amount, a method that has been often used from the past is that the value of the initial reagent amount is keyed in at the time of reagent replacement and stored in a memory, and the consumption amount is subtracted for each measurement. This was the method of managing the remaining amount.

However, this method is very cumbersome because it is necessary to input the value of the reagent amount each time the reagent is replaced, and it is easy to induce an input error. Moreover, since the time spent for key operation is enormous, it is not practically usable in daily routine work.

In order to solve such a problem, there is a method of detecting the presence or absence of a reagent by using, for example, a conductive sensor. As a recent example using this conductivity sensor, Japanese Patent Laid-Open No.
The analyzer disclosed in Japanese Patent Laid-Open No. 5-10958 is known.

This analyzer is equipped with two electrode wires (conductive sensors) that are welded to both ends of a reagent suction tube and have a contact near the tip, and monitor the conduction and non-conduction of these electrode wires to detect the reagent. The presence or absence was detected.

[0008]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
According to the analyzer disclosed in Japanese Patent Publication No. 0958, the operability is improved because the key input operation required for each reagent replacement is not required. However, the reagent amount is provided only as an ON / OFF signal due to the physical characteristics of the sensor, and the real-time property or continuity as a monitor is insufficient,
Comprehensive reagent management was difficult. Moreover, the operator must always pay attention to the warning of the remaining amount of the reagent, and the burden is still heavy.

On the other hand, since deterioration of the reagent adversely affects the accuracy of the analysis result, efforts are being made to avoid it. In consideration of such a situation, as in the analyzer disclosed in Japanese Patent Laid-Open No. 05-10958, in the method of directly contacting the electrode wire with the reagent for detecting the presence / absence of conduction of the reagent, platinum is applied to the electrode wire. It is necessary to use expensive materials such as, which has been a cause of cost increase.

Further, according to another example disclosed in Japanese Patent Laid-Open No. 05-10958, in order to solve the problem of cost increase due to contact between the electrode wire and the reagent, the reagent container is mounted on a metal plate. And shows the method of detecting the reagent remaining amount by the electrostatic capacitance between the electrode wire and the metal plate. However, in such a method of directly detecting the capacitance of the entire reagent container,
Since no consideration is given to the detected capacitance (1) being affected by the shape and material of the reagent container (2) being affected by the stray capacitance between the electrode wire and the device housing, It was difficult to accurately detect the reagent remaining amount.

The present invention has been made in view of the above problems, and a first object thereof is to provide an automatic chemical analyzer capable of accurately and in real time monitoring the remaining amount of a reagent while reducing the burden on the operator. Is.

A second object of the present invention is to prevent the deterioration of the reagent, and to continuously and in real time maintain the remaining amount of the reagent without being affected by the stray capacity caused by the shape of the reagent container or the device housing. It is to provide an automatic chemical analyzer capable of monitoring.

[0013]

In order to solve the above-mentioned object, in the automatic chemical analyzer according to claim 1, the liquid reagent is transferred from the inside of the liquid container containing the liquid reagent to a reaction container via a reagent dispensing tube. While automatically dispensing the liquid reagent based on the change in capacitance according to the liquid surface height of the liquid reagent detected by the sensor unit inserted in the container. A chemical analyzer,
The sensor unit includes a pair of electrodes having a required length for detecting the capacitance, and an electrode support body that includes and supports the pair of electrodes in the depth direction of the liquid container and is formed in a liquid-tight structure. It has and.

Further, in particular, in the automatic chemical analyzer according to the second aspect, the electrode support is a column made of an insulator, and a pair of blind holes are bored along the axial direction of the column. Then, the pair of electrodes are inserted into the blind holes.

Further, in the automatic chemical analyzer according to claim 3, the column is made of a material having a specific gravity of 1 or more,
A through hole is bored in the center of the column body along the axial direction, and the tube is inserted in the through hole so that the suction port of the tube is in contact with the bottom surface of the column body.

On the other hand, in order to achieve the above object, a fourth aspect of the present invention is provided.
In the automatic chemical analyzer described in 1, a liquid container containing a liquid reagent, a reagent dispensing tube for dispensing the liquid reagent from the liquid container to a reaction container, and the liquid container inserted into the liquid container and A sensor unit for detecting a capacitance change according to the liquid level of the reagent, an output line for taking out the capacitance change detected by the sensor unit, and a pair of output terminals are provided. Is an electric chemical signal, and an automatic chemical analysis device configured to monitor the remaining amount of the liquid reagent based on the electric signal output from the converting means, wherein the sensor unit is the static sensor. A pair of electrodes composed of a first electrode and a second electrode having a required length for capacitance detection, and the pair of electrodes were enclosed and supported in the depth direction of the liquid container and formed into a liquid-tight structure. While having an electrode support, Serial output lines and having a shield section that shields the two cables comprising a first and a second cable, the two cables, said first
And a second cable respectively connected to the pair of output terminals of the conversion means, the first electrode connected to the ground, the second electrode connected to the first cable, and the second cable One end of the cable is used as an open end.

Particularly, in the automatic chemical analyzer according to the fifth aspect, there are a plurality of the liquid containers, each of the plurality of liquid containers is provided with the sensor section, and each of the plurality of sensor sections has the output. While connecting the lines, there is provided selection means for selecting one output signal from the output signals respectively sent through the plurality of output lines and sending it to the conversion means.

[0018]

According to the automatic chemical analyzer of claim 1, the sensor part inserted in the liquid container containing the liquid reagent is for detecting a capacitance change according to the liquid surface height of the liquid reagent. And a pair of electrodes having a required length, and an electrode support body which is formed in a liquid-tight structure by enclosing and supporting the pair of electrodes in the depth direction of the liquid container. That is, since the liquid reagent and the electrode are not in contact with each other by the electrode support, there is no influence on the composition of the liquid reagent even when the capacitance change is detected by the electrode.

Particularly, in the invention described in claim 2 or 3, the electrode support is a columnar body made of an insulator having a specific gravity of 1 or more, for example, and the pair of electrode holes is provided along the axial direction of the columnar body. A pair of electrodes are inserted in the blind holes. Then, a tube is inserted in a through hole formed along the axial direction at the center of the column body such that its suction port is in contact with the bottom surface of the column body. As a result, the columnar body is placed on the bottom surface of the liquid container due to the specific gravity, and the suction port of the tube also contacts the bottom surface of the container. Therefore,
The suction operation of the liquid reagent is performed well.

On the other hand, in the invention described in claim 4, as in the invention described in claim 1, the sensor portion is provided with the first and second electrodes of a required length for capacitance detection. And a pair of electrodes, and an electrode support body that encloses and supports the pair of electrodes in the depth direction of the liquid container, and that is formed in a liquid-tight structure, on the other hand, electrostatic detected by the pair of electrodes. The capacitance is sent to the conversion means via an output line having two cables shielded by the shield part.

In the converting means, the sent capacitance change is converted into an electric signal, and this electric signal is taken out through a pair of output terminals. Then, the remaining amount of the liquid reagent is monitored based on this electric signal.

At this time, the two cables consisting of the first and second cables are respectively connected to the pair of output terminals of the converting means, the first electrode is connected to the ground, and the second electrode is connected to the first electrode. It is connected to the cable of
One end of the second cable is an open end.

That is, one output terminal of the converting means is the first
Is connected to the second electrode via the cable and the other output terminal is connected to the second cable, and its tip is an open end. Also, the first electrode is connected to the ground.

As a result, it can be considered that the capacitance between the first and second electrodes is connected to one output terminal of the conversion means (the first electrode is connected to the ground). From). Further, since the tip of the second cable connected to the other output terminal of the conversion means is an open end, the stray capacitance caused by the cable acting between both output terminals of the conversion means is canceled out between both terminals. It Therefore, the influence of the stray capacitance caused by the cable can be eliminated.

Further, in the invention described in claim 5, a sensor portion is provided in each of the plurality of liquid containers.
An output line is connected to each of the plurality of sensor units.

At this time, if it is desired to monitor the amount of liquid remaining in a certain container among the plurality of containers, the selecting means selects the desired container from the output signals respectively sent through the plurality of output lines. The output signal of the corresponding one output line is selected and sent to the conversion means. That is, it is possible to monitor the remaining amount of the liquid reagent in real time with respect to any of the plurality of liquid containers by appropriately selecting with the selecting means.

[0027]

EXAMPLES An example of the automatic chemical analyzer according to the present invention will be described below with reference to FIGS.

FIG. 1 is a schematic block diagram of a discrete-type multi-item, multi-specimen automatic chemical analyzer (hereinafter, simply referred to as an analyzer) for simultaneously analyzing a plurality of types of items, in order to avoid complexity. , Mainly shows the components related to the operation when the remaining amount of the reagent is monitored.

This automatic chemical analyzer is equipped with a reaction system 1, a reagent dispensing system 2, and a reagent remaining amount monitor system 3. Further, some components of the reagent dispensing system 2 and the reagent remaining amount monitor system 3 overlap.

The reaction system 1 comprises a plurality of (only one in the figure) reaction tubes 5 arranged on a circular reaction line 4 in a disk-shaped reaction disk (not shown). A liquid sample (specimen) is accommodated in the reaction tube 5 and is intermittently transferred to the reagent dispensing position. A plurality of reagent containers 6a to 6d containing liquid reagents are arranged, for example, above the reaction tube 5 at the reagent dispensing position.

In each of the reagent containers 6a to 6d, suction tubes 7a to 7d for sucking the reagent and parallel electrode wires (hereinafter also referred to as sensor electrode wires) for monitoring the remaining amount of the reagent (8a1, 8a2).
) To (8d1, 8d2) are held together, and holding bases 9a to 9d are installed. This holding base 9a-9
The schematic structure of d is shown in FIGS.
Shows only the schematic configuration of the holding base 9a, and the other holding bases 9b to 9d have the same configuration). The sensor electrode wires (8a1, 8a2) and the holding base 9a
To form the sensor section SEa (similarly, the other sensor electrode wires (8b1, 8b2) to (8d1 and 8d2) and the holding bases 9b to 9d also form the sensor section SEb to the sensor section SEd).

The holding base 9a is a substantially cylindrical body, and the container 6
It is installed in the container 6a in an upright state such that the long axis direction of the holding base 9a is along the depth direction of a. Then, a through hole is formed in the central axis portion of the holding base 9a, and a suction tube 7a for sucking the reagent is inserted into the through hole as shown in FIG. The suction port at the suction side tip of the suction tube 7a has a reagent container 6a.
It touches the bottom.

In addition, a pair of blind holes are formed in the holding base 9a along the axial direction thereof at a predetermined distance, and electrode wires (sensor electrode wires 8a1) are formed in the pair of blind holes.
) And (sensor electrode wire 8a2) are buried. Of the sensor electrode wires (8a1, 8a2), one of the electrode wires 8a1 is, for example, a metal body of a mesh structure (from the upper surface of the holding base 9a via the connection lead-out portion 10 as shown in FIG. 2A). It is connected to one of the "pair wires (11a1, 11a2) (a pair of cables)" (the cable 11a1) that is electromagnetically shielded by being covered by the shield portion S). The other of the pair of cables (cable 11a2
The end on the sensor side of) is an open end.

The other electrode wire 8a2 is connected to the end of the shield part S on the sensor part side via a separate cable 11ca. At this time, the sensor electrode wires (8a1, 8a
2) is the connection lead-out part (also called the lead wire lead-out part)
It has a liquid-tight structure in which the reagent solution including 10 is not permeated.

Further, a plurality of (four in FIG. 1) discharge tubes 12a to 12d for discharging the reagent to the reaction tube 5 are arranged above the reaction tube 5. The discharge tubes 12a to 12d are held in a fixed state by the reagent slider 13. Then, the plurality (four in FIG. 1) of the discharge tubes 12a to 12d are selected by the movement of the slider 13 in the direction of the arrow s by the slider driving mechanism 14, and are positioned at the reagent dispensing position.

The automatic chemical analyzer is equipped with syringes 15a to 15d for sucking and discharging the reagent. The common tubes 16a to 16d that also serve as the suction path and the discharge path of the syringes 15a to 15d are suction tubes 7a by a three-way switching valve (hereinafter also referred to as switching valve) V.
7d and the discharge tubes 12a to 12d are selectively connected. The reagent containers 6a to 6d, the suction tubes 7a to 7d, the discharge tubes 12a to 12d, the slider 1
3, slider drive mechanism 14, and syringes 15a-15
d constitutes the reagent dispensing system.

On the other hand, pair wires (11a1, 11a2) to
(11d1, 11d2) are connected to the respective input terminals of the multiplexer 17. The multiplexer 17
Includes a pair of input terminals to which a pair of signal lines can be connected, at least as many as the reagent containers 6a to 6d. The plurality of input terminals are also referred to as channels hereinafter.
The end of the shield S on the multiplexer 17 side (the end opposite to the connection end of the cable 11ca) is connected to the ground.

Here, FIG. 3 shows the connection structure between the sensor electrode wires (8a1, 8a2) in a certain reagent container 6a and the multiplexer 17. The cable 11a1 connected to one of the sensor electrode wires (8a1, 8a2) 8a1 passes through the shield portion S and is connected to one of the pair of input terminals of the multiplexer 17 xa1. Also, multiplexer 1
The cable 11a2 connected to the other xa2 of the pair of input terminals 7 extends through the shield S to the sensor section side, and the tip on the sensor section side is in the open state as described above. Incidentally, the connection of the electrode wires (8b1, 8b2) to (8d1, 8d2) in the other reagent containers 6b to 6d is similarly performed by the pair wires (11b1 and 11b2) to (11d1).
, 11d2) and cables 11cb to 11cd.

In this way, all reagent containers 6a-6
d sensor electrode wires (8a1, 8a2) to (8d1, 8d)
One cable (11a1 to 11d1) of the pair wire connected to one (8a1 to 8d2) of d2) is connected to one input terminal (xa1 to xd1) of the multiplexer 17,
The other cables (11a2 to 11d2) of the paired wires are connected to the other input terminals (xa2 to xd2) of the multiplexer 17.

FIG. 3 also shows a schematic structure of the reagent remaining amount monitor system 3. This reagent remaining amount monitor system is composed of the above-mentioned sensor electrode wires (8a1, 8a2) to (8d1, 8d2).
), And a multiplexer 17 as part of the components.

The output of the multiplexer 17 is connected to the reagent remaining amount monitor signal detection circuit 18. An A / D converter 19, a remaining amount monitor signal control / calculation unit 20, and a TV monitor 21 are connected to the output side of the reagent remaining amount monitor detection circuit 18. An input unit 22 and an alarm buzzer generation unit 23 are connected to the remaining amount monitor signal control / arithmetic unit 20, and the multiplexer 20 has an address latch circuit 24.
Is connected. Furthermore, the reagent remaining amount monitor system 3
Includes a system control unit 25 that controls the entire system.

The reagent remaining amount monitor signal detection circuit 18 is shown in FIG.
As shown in, an oscillator (oscillator) 26 that oscillates a sine wave signal having an angular frequency ω is provided. This oscillator 2
On the output side of 6, a bridge circuit 27, an instrumentation amplifier 28,
The full-wave rectifier 29 and the low-pass filter 30 are sequentially connected.

A pair of output terminals "ya (for input terminals xa1 to xn1), y, which are the only output terminals of the multiplexer 17,
b (for input terminals xa2 to xn2) "are connected to the output terminals P1 and P2 of the bridge circuit 27, respectively. That is, the bridge circuit 27 uses the sensor electrode lines {(8a1, 8a2) to (8d1, 8) selected by the multiplexer 17.
The capacitance between one of d2)} is made a part of the component. The output terminal P1 of the bridge circuit 27 is connected to the negative phase terminal (−input) of the instrumentation amplifier 28, and the output terminal P2 is connected to the positive phase terminal (+ input) of the instrumentation amplifier 28. Furthermore, a compensation capacitance (capacitor) 31 is connected to the terminal P2 (+ input side of the instrumentation amplifier 28). The compensating capacitor 31 is a bridge circuit 27 generated because only one of the pair lines (11a1, 11a2) to (11d1, 11d2) is connected to the sensor electrode lines (8a1, 8a2) to (8d1, 8d2).
Is provided to compensate for the imbalance of the. The value of the compensation capacitor 31 in this embodiment is several pF to several tens pF.

An equivalent circuit of the bridge circuit 27 is shown in FIG. 4 (it is assumed that the multiplexer 17 selects the input terminals (xa1, xa2) of the sensor electrode lines (8a1, 8a2)). In the figure, R is the value of the bridge resistance of the bridge circuit 27, C0 is the shielded pair wire (11a
1, 11a2), Cx is the sensor unit S
The capacitance produced when Ea is immersed in the reagent, and C1 is the value of the compensation capacitance. Further, the sine wave applied voltage applied from the oscillator 26 is ei, and the voltages at both terminals P1 and P2 of the bridge circuit 27 are e1 and e, respectively.
Set to 2.

As is clear from the equivalent circuit of FIG. 4, the stray capacitance from the bridge circuit 27 to the sensor electrode wires (8a1, 8a2) is due to the structure of the shielded pair wire (11).
a1 and 11a2) have their own equal capacitances C0 (hereinafter referred to as intrinsic capacitances) and can be regarded as being connected to both terminals P1 and P2 sandwiching the ground of the bridge circuit 27, respectively. That is, both terminals P1 and P
The specific capacitance C0 connected to 2 will cancel out.

Furthermore, this pair of paired wires (11a1, 1
1a2) is electromagnetically shielded, so the influence of stray capacitance from the bridge circuit 27 to the sensor electrode wires (8a1, 8a2) is affected by a pair of shielded cables (11a2).
a1 and 11a2), and the value of the capacitance is determined by the cable length. Therefore, the influence of the stray capacitance from the surrounding environment due to how the cable is routed on the device casing and attached is neglected.

Therefore, the output voltage of the bridge circuit 27 (the potential difference (e between the terminals P1 and P2 of the bridge circuit 27 (e
1-e2)} is the change (Δ) in the capacitance Cx that occurs when the sensor section SEa having the sensor electrode lines (8a1, 8a2) selected by the multiplexer 17 is immersed in the reagent.
Cx). In other words, the capacitance change ΔCx between the sensor electrode wires (8a1, 8a2) can be obtained as the output voltage of the bridge circuit 27.

The output voltage (e1-
The signal e2) is differentially amplified by the instrumentation amplifier 28 and then taken out as an average value (hereinafter referred to as a sensor signal) via the full-wave rectifier 29 and the low-frequency filter 30. In addition, the multiplexer 17 uses the sensor electrode line (8
b1 and 8b2) to (8d1 to 8d2) terminals (xb1, x)
The case where b2) to (xd1, xd2) is selected is the same as the case of the terminals (xa1, xa2) of the sensor electrode wires (8a1, 8a2) described above.

This sensor signal is converted into digital data via the A / D converter 19 and then sent to the remaining amount monitor signal control / arithmetic unit 20.

The remaining amount monitor signal control / arithmetic unit 20 includes a memory and a local central processing unit (hereinafter referred to as CPU), and a control execution instruction sent from the system control unit 25 and input data sent from the input unit 22. Based on the above, the processing shown in FIG. 11 described later is performed.

The input unit 22 has, for example, a keyboard and the like, and various data can be input by the operator. The input data is sent to and stored in the memory of the remaining amount monitor signal control / arithmetic unit 20.

The alarm buzzer generator 23 sounds an alarm buzzer of a required size in response to an alarm buzzer generation command sent from the remaining amount monitor signal control / arithmetic unit 20.

The address latch circuit 24 temporarily holds the address signal for switching the output signal sent from the system control unit 25, and then the multiplexer 1 outputs the address signal.
It is supposed to be sent to 7.

The multiplexer 17 selects the data input to the input terminal (channel) corresponding to the address according to the address signal sent from the address latch circuit 24 and sends it to the output terminal.

Here, the relationship between various parameters and sensor output for monitoring the reagent remaining amount will be described.
In the following description, it is assumed that the multiplexer 17 selects the input terminals (xa1, xa2) of the sensor electrode lines (8a1, 8a2).

5A and 5B show the bridge resistance R
= 100 KΩ, capacitance change C when ei amplitude is 1
The relationship between the signal amplitude change of x and "e1 -e2" is shown. Frequency 5 KHz (Fig. 5 (a)) and 30 KHz (Fig. 5 (b))
In this case, C0 is used as a parameter. Signal voltage "e
1-e2 "becomes more sensitive as the frequency increases. On the other hand, however, the smaller the influence of the capacitance C0 on the signal voltage is, the more desirable it is, so the trade-off between the two is important. FIG. 6 shows a state of sensor output in various containers in the reagent remaining amount monitor in the present embodiment. The diameter of the bottom of a beaker with a capacity of 500 ml is about 83 mm,
The diameter of the bottom of a 500 ml capacity polybin is 72 mm and the capacity is 1.
The bottom diameter of 000 ml polybin is 100 mm. Since the shape and size of the container are different even for the same sample volume,
The height of each reagent surface changes. Therefore, there is a difference in the magnitude of the sensor output.

On the other hand, FIG. 7 shows the relationship between the liquid level height of the reagent and the sensor output in each container of FIG. As shown in FIG. 7, it is clear that the sensor output depends on the length of contact of the sensor electrode wire (8a1, 8a2) with the reagent regardless of the shape and size of the container.

FIG. 8 shows the relationship between the liquid level height and the sensor output due to some reagents. No difference in sensor output depending on the type of reagent was observed. It is considered that this is because the effect of the dielectric constant of water, which is a polar solvent, is more dominant than the dielectric constant of the components that make up the various reagents.

That is, the sensor electrode wires (8a1, 8a2)
Is a sensor output corresponding to a change in the length (that is, the liquid level height h of the reagent) wrapped in the reagent via the holding base 9a,
In other words, the electrostatic capacitance Cx between the sensor electrode wires (8a1, 8a2) changes. That is, the sensor electrode wire (8a1
, 8a2), the capacitance Cx is

## EQU1 ## Cx = ε ₁ + ε _x ) × h × S / d (1) where ε ₁ is the permittivity of the holding base 9a, ε _x is the permittivity of the region surrounding the holding base 9a, and S Is the area of the regions of the sensor electrode wires (8a1, 8a2) facing each other per unit length, and d is the distance between the sensor electrode wires (8a1, 8a2).

Therefore, the electrostatic capacitance Cx, that is, the sensor output changes as shown in FIG. 8 according to the liquid level.

Cx is the shape and size of the reagent container,
And that it is irrelevant to the type of reagent.

Furthermore, in the state where the actual remaining amount of the reagent is monitored, it is necessary to monitor the state where the reagent solution gradually decreases from the state where the reagent solution is filled in the container. Therefore, the solution that adheres to the sensor electrode wires (8a1, 8a2) and remains as it is may be added to the actual remaining amount, giving an erroneous result. Therefore, the design of the holding base 9a holding the sensor electrode wires (8a1, 8a2) is an important point for practical use. The holding base 9a has a function of holding the reagent tube 7a and also serving as a weight for making the suction port of the reagent tube 7a in contact with the bottom surface of the reagent container 6a. , Insulation, chemical resistance, specific gravity, and water rupture are important factors. Examples of materials that satisfy such conditions include fluororesin, polysulfone, and PEEK.

FIG. 2 shows an example of the schematic dimensions of the holding base 9a. It functions as a weight and the liquid level is 7
0 mm range (for example, bottom area 110 mm x 20 mm,
120 for a reagent container with a depth of 150 mm and an effective volume of 200 ml
The total length is "Dx = 80 mm" and "Diameter Dz = 9 mm" in consideration of the fact that the remaining amount can be monitored from the reagent amount (ml) and that the holding base 9a can be kept upright when placed in the container 6a. .

Here, FIG. 9 shows the sensor output characteristics as the reagent remaining amount is increased / decreased by the holding base 9a of this embodiment. Figure 9
The result of was obtained by the following measurement procedure. First, the reagent 200m
The holding base 9a was put into a reagent container 6a of a required size filled with 1 and the sensor output value at a predetermined liquid level was measured while sucking out the reagent little by little. Next, after washing the reagent container 6a and the holding base 9a, the sensor output value at a predetermined liquid level was measured while injecting an appropriate amount of reagent into the reagent container 6a this time. Furthermore, while injecting an appropriate amount of reagent into the reagent container 6a, a sensor output value corresponding to a predetermined liquid level height was measured. Subsequently, the sensor output value corresponding to a predetermined liquid level height was measured while reducing the amount of 200 ml of the reagent filled in the reagent container 6a again by an appropriate amount.

As is clear from FIG. 9, the slope of the sensor output is almost the same as the reagent amount increases and decreases. This indicates that the influence of the reagent remaining on the holding base 9a is small even if the amount of the reagent decreases.

In FIG. 2, the length D1 of the sensor electrode wire (8a1, 8a2) in the depth direction and the sensor electrode wire (8a1, 8a2) depending on the structure of the holding base 9a are the blindness of the holding base 9a. Since it is inserted in the hole, the length D2 in the depth direction of the insensitive body portion mainly caused by the meat pressure
(About 10 mm) and the length D3 in the depth direction of the connection drawing portion 10 are also shown. In the state where the reagent amount is gradually increased, as shown in FIG. 9, the sensor output shows an output change that is in good agreement with the structure of the holding base. The length D1 of the sensor electrode wires (8a1, 8a2) in the depth direction is
Compared to the total length Dx of the holding base 9a, Dy (for example, 5 m
m) shorter. This is because the height of the liquid surface is the length D1 of the sensor electrode wire (8a1, 8a2) due to the decrease in the amount of reagent.
This is because it is set so that the reagent still remains in the container 6a even when the sensor output of the sensor electrode wires (8a1 and 8a2) detects the drop.

On the other hand, in the state where the reagent gradually decreases from the state where the reagent is filled in the container 6a, adhesion of the reagent to the shielded pair wire connecting / drawing portion 10 is the main cause, and the liquid level is higher than the sensor electrode. The sensor output has a certain value even if it goes down beyond the length of the lines (8a1, 8a2) (referred to as a bias value at the time of reagent attachment). Therefore, in practice, the bias value at the time of reagent attachment determined in advance by such an experiment is obtained for each sensor electrode wire (8a1, 8a2), and the bias value is stored in the memory of the remaining amount monitor signal control / arithmetic unit 20. It is good to remember.

Further, in the above-mentioned measurement result when the reagent amount is reduced, for example, when the bottom area of the reagent container 6a is known, the reagent volume and the sensor output when the obtained liquid level height is converted into the reagent amount 10 shows the relationship. That is, when applied to the analyzer, the liquid level height of the reagent and the sensor output, or the reagent level and the sensor output when the liquid level height is converted into the reagent amount, as shown in FIG. Data such as a graph showing the relationship is created in advance based on a plurality of measurement data {hereinafter, data such as a graph showing the relationship between the reagent amount (or liquid level height) and the sensor output is referred to as calibration curve data. }. This calibration curve data can be used to control the remaining amount monitor signal via, for example, an external storage device (not shown).
The data is stored in the memory of the arithmetic unit 20.

Next, the entire operation will be described centering on the dispensing operation of the reagent and the monitoring operation of the remaining sample amount accompanying the dispensing operation.

Initially, the reagent remaining amount monitor system 3 is initially set when the analyzer is installed. That is, the reagent remaining amount monitor system 3 is activated in a state where the sensor portions SEa to SEd having the sensor electrode wires (8a1, 8a2) to (8d1, 8d2) are not immersed in the reagent. Then, the system controller 25 sequentially outputs address signals to the multiplexer 17 via the address latch circuit 24, and the sensor electrode lines (8a1, 8a2) to (8d1, 8d).
d2) sensor output (also called initial bias value; that is, imbalance of capacitance of shielded pair wire or holding base 9
a to 9d sensor electrode wires (8a1, 8a2) to (8d
1), 8d2), and an output generated due to a structural factor of the remaining amount monitor signal detection circuit 18, such as an electrostatic capacity, are stored in the memory of the remaining amount monitor signal control / arithmetic unit 20 via the A / D converter 19. I'll do it.

Before starting the analysis operation, the operator inputs in advance from the input section 22 a predetermined reagent remaining amount (that is, an amount at which it is difficult for the reagent to decrease further). This value is stored in the memory of the remaining amount signal control / arithmetic unit 20.

Then, the dispensing operation of the sample and the reagent is performed. That is, a predetermined amount of sample (sample) is dispensed to the reaction tube 5 at a sample dispensing position (not shown). Then, the reaction line 4 is rotationally moved, and the reaction tube 5 accommodating this sample is positioned at the reagent dispensing position A.

On the other hand, the reagent syringe corresponding to a predetermined test item is, for example, 15a. At this point, the common tube 16a and the suction tube 7 are switched by the switching operation of the switching valve V.
a is connected. Then, due to the suction operation of the reagent syringe 15a, the amount of reagent necessary for analysis is changed to the reagent container 6a.
Is sucked through the suction tube 7a.

After the predetermined amount of reagent is sucked in this way, the common tube 16a is connected to the discharge tube 12a by the switching operation of the switching valve V. At this time, the reagent slider 13 is moved to the reagent nozzle Na by the slider driving mechanism 14.
Is moved to the reagent discharge position on the reaction tube 5. Then, the discharge tube 12 is discharged by the discharge operation of the reagent syringe 15a.
A predetermined amount of reagent is discharged into the reaction tube 5 through the reagent nozzle Na. The reaction of the sample is obtained as a concentration or an activity value by optically measuring the reaction solution when the color reaction proceeds, for example.

When the discharge of the reagent is completed, the reaction tube 5 is moved to the next stirring position.

In this way, when the ejection operation of the reagent of the predetermined item is performed, the parallel electrode lines in the reagent container 6a in which the reagent is dispensed through the address latch circuit 24 under the control of the system control unit 25. An address signal for selecting the input terminals (xa1, xa2) corresponding to (8a1, 8a2) is sent to the multiplexer 17. Multiplexer 1
7, the input terminal (xa
1, xa2) sensor electrode wire (8a1, 8a2)
The electrostatic capacitance data between them is selected, and becomes the electrostatic capacitance change ΔCx of the bridge circuit 27 of the reagent remaining amount monitor signal detection circuit 18.

The bridge circuit 27 in the equilibrium state produces an output voltage in accordance with the capacitance change ΔCx, and this output voltage becomes a sensor signal via the full-wave rectifier 29 and the low-pass filter 30. . Then, this sensor signal is stored in the memory of the remaining amount monitor signal control / arithmetic unit 20 as sensor output data via the A / D converter 19.

At this time, the remaining amount monitor signal control / calculation unit 2
0 performs the processing shown in FIG. 11 based on the operation of the CPU. That is, the remaining amount monitor signal control / arithmetic unit 20
Subtracts the initial bias value and the reagent adhesion bias value stored in the memory from the sensor output data sent from the A / D converter 19 (step 101). The data obtained by this subtraction is stored in the memory as new sensor output data.

Subsequently, the remaining amount monitor signal control / arithmetic unit 20
Reads the reagent remaining amount and the calibration curve data stored in the memory, and obtains the sensor output value (threshold value) corresponding to the set reagent remaining amount by referring to the calibration curve data (step 1
02).

The remaining amount monitor signal control / arithmetic unit 20
Indicates that the level Vr of the new sensor output data is the threshold level Tr.
It is determined whether or not it is further decreased (step 103), and if it is decreased (YES determination), an alarm buzzer generation command is sent to the alarm buzzer generation unit 23 (step 104), and the process is ended. If it has not decreased (NO judgment),
Before returning to the execution of step 101, the next sensor output is waited for, and the above-described processing is repeated each time the sensor output is input. Then, such a series of operations is repeated one after another in each cycle according to the inspection content or the like.

In this way, the remaining amount monitoring operation described above is repeated for each dispensing operation of the reagent. Then, if the sensor output corresponding to the reagent remaining amount falls below the threshold value, an alarm buzzer generation command is sent to the alarm buzzer generation unit 23 by the processing of step 104. As a result, the alarm buzzer generator 23 sounds an alarm buzzer to notify the operator of the limit of the reagent remaining amount.

As described above in detail, according to this embodiment, the sensor portion provided on the reagent container is connected to the sensor electrode wires {(8a1, 8a2) to (8d1, 8d2)} and the holding bases 9a to 9d. The sensor electrode wire {(8a1,
8a2)-(8d1, 8d2)} with one electrode wire as the ground, the sensor electrode wire {(8a1, 8a2)-
The capacitance between (8d1, 8d2)} is detected. Also,
Sensor electrode wires {(8a1, 8a2) to (8d1, 8d2
)} And the line connecting the bridge circuit 27 with shielded pair wires {(11a1, 11a2) to (11d1)
, 11d4)}.

Therefore, since the capacitance between the electrode lines changes in response to the change in the sample liquid level regardless of the influence of the change in the shape, size, or material of the reagent, the remaining amount of the reagent is continuously monitored in real time. it can.

The sensor electrode wires {(8a1, 8a2) to (8d1, 8d2)} provided on the reagent container have a liquid-tight structure insulated from the reagent via the holding bases (9a to 9d). Therefore, even if the capacitance change between the electrode lines is detected in real time, there is no influence on the reagent composition.

In the above-described operation, a method has been shown in which only the sensor signal of the container 6a from which the reagent has been discharged is taken into the remaining amount monitor signal control / arithmetic unit 20, but the input terminals of the multiplexer 17 are switched one after another and each cycle is changed. All sensor signals may be rewritten every time.

Further, a plurality of thresholds are set, and information corresponding to several layers such as stop of the sampling operation of the apparatus due to reagent exhaustion, warning of insufficient reagent amount, caution of insufficient reagent amount, etc. is given by, for example, a warning buzzer or the like. It may be provided to the operator.

Further, the structure of the holding bases 9a to 9d is as follows.
In this embodiment, a substantially cylindrical body is used as shown in FIG.
The present invention is not limited to this, and as described above, it can function as both a function of holding the reagent tube and a function of a weight for making the suction port of the reagent tube in contact with the bottom surface of the reagent container. Any shape such as a polygonal prism may be used.

[0088]

According to the present invention, a pair of required lengths for detecting a capacitance change according to the liquid surface height of the liquid reagent, which is a constituent element of the sensor unit inserted in the liquid container, is provided. The electrodes are
Since it is contained and supported in the depth direction of the liquid container by the electrode support formed in the liquid-tight structure, it is possible to detect the capacitance change between the electrode lines without any influence on the reagent composition.

Further, according to the present invention, the output line for taking out the capacitance change detected by the pair of electrodes composed of the first and second electrodes has the two cables composed of the first and second cables. And a shield portion for shielding the two cables, and connecting the first and second cables to a pair of output terminals of the conversion means, connecting the first electrode to the ground, and Since the two electrodes are connected to the first cable, it can be considered that the capacitance between the pair of electrodes is connected to one output terminal of the conversion means. Therefore, the capacitance change between the electrodes according to the change of the liquid level can be obtained as the output signal converted by the converting means. Furthermore, since the tip of the second cable connected to the other output terminal of the conversion means is an open end, the stray capacitance due to the cable that acts between both output terminals of the conversion means cancels out between both terminals. Therefore, it is possible to eliminate the influence of stray capacitance caused by the cable.

Therefore, the capacitance between the electrode lines changes regardless of the influence of the change in the shape, size, or material of the reagent, and in response to the change in the liquid level of the reagent without causing the deterioration of the reagent. The reagent remaining amount can be continuously and accurately monitored in real time.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of an automatic chemical analysis device according to a first embodiment of the present invention.

FIG. 2A is a diagram showing a schematic configuration of a holding base that holds both a suction tube and a sensor electrode wire. Figure 2 (b) is
A sectional view taken along the line A-A in (a).

FIG. 3 is a diagram showing a connection configuration between parallel electrode lines in a reagent container and a multiplexer and a schematic configuration of a reagent remaining amount monitoring system.

FIG. 4 is a diagram showing an equivalent circuit of a bridge circuit.

FIG. 5 is a graph showing the relationship between capacitance change and sensor signal amplitude change.

FIG. 6 is a graph showing sensor outputs of various containers.

FIG. 7 is a graph showing the relationship between liquid level height and sensor output in various containers.

FIG. 8 is a graph showing sensor output by various reagents.

FIG. 9 is a graph showing sensor output characteristics according to an increase / decrease in the amount of reagent of the holding base for sensor of the present embodiment.

FIG. 10 is a graph showing the relationship between the reagent remaining amount and the sensor output by the sensor holding base of the present embodiment.

FIG. 11 is a schematic flowchart showing an example of processing in a remaining amount monitor control / arithmetic unit.

[Explanation of symbols]

1 Reaction System 2 Reagent Dispensing System 3 Remaining Amount Monitor System 4 Reaction Line 5 Reaction Tube 6a to 6d Reagent Container 7a to 7d Suction Tube (8a1, 8a2) to (8d1, 8d2) Sensor Electrode Wire 9a to 9d Holding Base 10 Connection drawing section (11a1, 11a2) to (11d1, 11d4) Pair wire 11ca to 11cd cable 17 Multiplexer 18 Remaining amount monitor signal circuit 19 A / D converter 20 Remaining amount monitor signal control / arithmetic unit 21 TV monitor 22 Input unit 23 Alarm buzzer generator 24 Address latch circuit 25 System controller 26 Oscillator 27 Bridge circuit 28 Instrumentation amplifier 29 Full-wave rectifier 30 Low-pass filter S Shield SEa-SEd Sensor

Claims (5)

[Claims] 1. A liquid reagent which is dispensed from a liquid container containing a liquid reagent into a reaction container through a reagent dispensing tube, and which is detected by a sensor unit inserted in the container. Is an automatic chemical analysis device for monitoring the remaining amount of the liquid reagent based on a change in capacitance according to the liquid level height of the sensor unit, the sensor unit is a required length for the capacitance detection. 2. An automatic chemical analysis device comprising: a pair of electrodes, and an electrode support body that includes and supports the pair of electrodes in the depth direction of the liquid container and that is formed in a liquid-tight structure. 2. The electrode support is a column made of an insulating material, and a pair of blind holes are bored along the axial direction of the column, and the pair of electrodes are inserted into the blind holes. The automatic chemical analyzer according to claim 1. 3. The column body is made of a material having a specific gravity of 1 or more, and a through hole is formed in the center of the column body along the axial direction,
The automatic chemical analyzer according to claim 2, wherein the tube is inserted into the through hole so that the suction port of the tube is in contact with the bottom surface of the column. 4. A liquid container containing a liquid reagent, a reagent dispensing tube for dispensing the liquid reagent from the liquid container to a reaction container, and a liquid surface of the liquid reagent inserted into the liquid container. A sensor unit that detects a capacitance change according to the height, an output line that takes out the capacitance change detected by the sensor unit, and a pair of output terminals, and the capacitance change into an electric signal. An automatic chemical analysis device, comprising: a conversion unit for converting, and monitoring the remaining amount of the liquid reagent based on an electric signal output from the conversion unit, wherein the sensor unit is for detecting the capacitance. First of the required length of
And a pair of electrodes composed of a second electrode, and an electrode supporter that includes and supports the pair of electrodes in the depth direction of the liquid container and that is formed in a liquid-tight structure, while the output line is It has two cables consisting of a first cable and a second cable, and a shield part for shielding the two cables, and connects the first cable and the second cable to a pair of output terminals of the conversion means, respectively. Then, the first electrode is connected to the ground, the second electrode is further connected to the first cable, and one end of the second cable is an open end, which is an automatic chemical analysis. apparatus. 5. The liquid container has a plurality of liquid containers, and the sensor unit is provided in each of the plurality of liquid containers.
The output line is connected to each of the plurality of sensor units, and a selection unit that selects one output signal from the output signals respectively sent through the plurality of output lines and sends the selected output signal to the conversion unit. The automatic chemical analysis device according to claim 4.