JPH10232156A - Liquid quantity detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the erroneous detections by the restriction of the kinds of fluids and bubbles and to make it possible to detect liquid quantity without lowering a sucking nozzle by providing a pressure gage between a container and a pump, and detecting the pressure in a drain pipe. SOLUTION: When liquid is injected into a liquid storing part 1a of a container 1 from a sucking nozzle 2, the pressure in a drain pipe 3 is increased in accordance with the liquid quantity, and the detected signal of the voltage corresponding to the pressure is outputted from a pressure gage 6. A control device operates the liquid quantity, the position of the liquid surface and the like in the container 1 as required from the detected signal of the pressure gate 6. When the liquid injection more than the specified quantity is confirmed in the liquid storing part 1a, the control device sucks the specified amount of the liquid in the liquid storing part 1a with the sucking nozzle 2 and supplies the liquid to the specified parts such as an analyzing part. Then, the control device performs the communication of an input port 4i and a normally closed port 4c and the regression of a cylinder 7a and sucks the liquid in the liquid storing part 1a into a pump 7. Thereafter, the control device communicates with the input port 4i and a normally opened port 4q, advances the cylinder 7a and discharges the surplus liquid in the pump 7 into the specified parts.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid amount detecting device for detecting a liquid amount in a container.

[0002]

2. Description of the Related Art For example, in an inspection apparatus for automatically inspecting a test liquid such as blood or urine, the test liquid is once poured into a predetermined container, and a predetermined amount of the test liquid is injected from this container by a suction nozzle. Is often supplied to the analysis unit after suctioning the sample. With this configuration, when the test liquid needs to be heated, the test liquid can be heated to a predetermined temperature in the container. In addition, when it is necessary to generate a test liquid by diluting with a predetermined diluent such as blood, the blood and the diluent are injected into the container, and the test liquid is caused to flow by flowing these liquids. Can be sufficiently mixed.

In such an inspection apparatus, measures such as discharging the test liquid remaining in the container after the suction by the suction nozzle, ie, excess liquid, each time, and cleaning the flow path of the test liquid including the container with the cleaning liquid are used. Necessary, drain piping is connected to the container.

By the way, in order to suck a predetermined amount of the test liquid from such a container with a suction nozzle, it is assumed that a predetermined amount or more of the test liquid is present in the container. In addition, when it is necessary to generate a test liquid by diluting with a predetermined diluent such as blood, the concentration of the test liquid changes beyond an allowable range if the amount of the diluent greatly differs, It is necessary to check whether a certain amount of the test liquid has been injected into the container.

For this reason, in the conventional liquid amount detecting device, a method of detecting the liquid amount of the test liquid in the container based on the conductivity between the pair of electrodes, a method of detecting the amount of the test liquid in the container by blowing air from a suction nozzle or another nozzle, or the like. Has been applied to the liquid surface of the test liquid, and the liquid surface is detected by a change in pressure in the nozzle. That is, since the relationship between the amount of the test liquid in the container and the height of the liquid level is always uniquely determined in the same container, the amount of the test liquid can be known by detecting the liquid level. is there.

However, in a system using a pair of electrodes,
Since the conductivity changes due to the attachment of dust, test liquid, and the like to the electrodes, an error exceeding a permissible range may occur in the liquid level detection. Furthermore, since the conductivity greatly differs depending on the type of the test liquid, there is also a problem that the test liquid that can be used is limited.

In the method in which air is ejected from the nozzle, an erroneous detection may occur when a film such as a bubble exists on the liquid surface of the test liquid. Further, since the nozzle is moved up and down, the amount of the test liquid cannot be detected until the nozzle reaches the vicinity of the liquid surface, and when the predetermined amount of the test liquid does not exist in the container, the operation of the nozzle is useless. There was a problem of becoming.

[0008]

DISCLOSURE OF THE INVENTION The present invention has been conceived under the circumstances described above, and is not limited by the types of liquids that can be detected, and can cause erroneous detection due to dirt or bubbles. SUMMARY OF THE INVENTION It is an object of the present invention to provide a liquid amount detection device which can detect the liquid amount without lowering the suction nozzle without lowering the suction nozzle.

In order to solve the above problems, the present invention takes the following technical measures.

According to a first aspect of the present invention, there is provided a liquid amount detecting device for detecting a liquid amount in a container capable of discharging surplus liquid through a drain pipe by a pump, wherein the container and the pump are connected to each other. A liquid amount detecting device is provided, comprising a pressure detecting means for detecting a pressure in the drain pipe between the two.

With this configuration, the pressure in the drain pipe increases in accordance with the amount of the liquid in the container, and the amount of the liquid in the container can be determined by detecting the pressure. The type of liquid that can be used is not limited, and erroneous detection due to dirt or bubbles does not occur, and the amount of liquid can be detected without lowering the suction nozzle. That is, since the electrodes are not used, they are not affected by contamination of the electrodes and the like, and the conductivity between the electrodes is not used. Therefore, detection is possible regardless of the conductivity of the liquid. Further, since the ejection of air from the suction nozzle is not used, the detection can be performed without being affected by bubbles on the liquid surface and without lowering the suction nozzle.

This liquid amount detecting device can be used not only for an automatic blood test device or an automatic urine test device, but also for detecting the liquid amount of any liquid other than blood and urine.

According to a preferred embodiment, the drain pipe can communicate with the pump via the electromagnetic switching valve, and is closed by the electromagnetic switching valve when not communicating with the pump.

With this configuration, the state in which the surplus liquid, the cleaning liquid, or the like is discharged by the pump and the other state can be very easily switched by the control signal of the electromagnetic switching valve.

According to another preferred embodiment, the pressure detecting means has a pressure sensor for outputting a signal of a voltage corresponding to the pressure in the drain pipe.

With this configuration, by supplying a signal from the pressure sensor to the control device, the presence / absence, amount, and level of the liquid in the container can be easily calculated. Can be controlled freely.

According to another preferred embodiment, the drain pipe is provided with a filter for removing impurities at an appropriate position between the container and the pump, and the pressure detecting means is provided between the container and the filter. Detect the pressure in the drain pipe.

With this configuration, it is possible to know whether the filter is clogged or the like based on the result of detection by the pressure detecting means.

According to another preferred embodiment, a switching valve is provided in the drain pipe between the filter and the pump so that the inside of the drain pipe can communicate with the atmosphere.

With this arrangement, when the pressure between the filter and the pump in the drain pipe becomes negative after the pump is driven due to clogging of the filter, the drain pipe is communicated with the atmosphere by the switching valve to reduce the pressure. Pressure can be eliminated. Therefore, it is possible to prevent the liquid in the container or the drain pipe between the container and the filter from gradually leaking into the drain pipe after the filter due to the negative pressure.

[0021] Other features and advantages of the present invention will become more apparent from the detailed description given below with reference to the accompanying drawings.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be specifically described below with reference to the drawings.

FIG. 1 is a schematic structural view of a liquid amount detecting device according to the present invention. The container 1 has a liquid reservoir 1a whose lower end is tapered downward. In 1a,
The liquid is injected and sucked by the suction nozzle 2. A drain pipe 3 is connected to a lower end of the liquid reservoir 1a.
An electromagnetic valve 4 as an electromagnetic switching valve is interposed in the drain pipe 3, and between the electromagnetic valve 4 and the container 1,
A filter 5 for removing impurities such as dust in the surplus liquid is provided. The drain pipe 3 includes the container 1 and the filter 5
And a pressure gauge 6 as pressure detecting means. In the solenoid valve 4, the normally closed port 4 c is connected to the upstream side of the drain pipe 3, and the normally open port 4 o is connected to the downstream side of the drain pipe 3. The input port 4i of the solenoid valve 4 is
It is connected to a pump 7. The suction nozzle 1 and the piston 7a of the pump 7 are driven by a driving mechanism (not shown),
The drive mechanism and the electromagnetic valve 4 are controlled by a control device (not shown) including a microcomputer and the like. A detection signal from the pressure gauge 6 is input to this control device. The liquid reservoir 1a of the container 1 has a diameter of, for example, about 10 mm and a depth of, for example, about 30 mm.

Next, the operation will be described. Liquid reservoir 1a of container 1
When the liquid does not exist, the inside of the drain pipe 3 is at atmospheric pressure, and the pressure sensor built in the pressure gauge 6 outputs a detection signal of a voltage corresponding thereto. The suction nozzle 2 moves onto the container 1 and the liquid is stored in the liquid reservoir 1 of the container 1.
When the liquid is injected into a, the pressure in the drain pipe 3 increases according to the amount of the liquid, and a detection signal of a voltage corresponding to the pressure is output from the pressure gauge 6. At this time, the connecting portion of the liquid reservoir 1a with the drain pipe 3 is formed to have a small diameter, and
Since the normally open port 4 c of the solenoid valve 4 is closed and the inside of the drain pipe 3 is closed, the liquid does not flow into the drain pipe 3. Therefore, the control device uses the relationship between the specific gravity of the liquid or the amount of liquid in the liquid reservoir 1a of the container 1 and the liquid level, which is stored in advance in a memory or the like, to thereby detect the detection signal from the pressure gauge 6. , The amount of the liquid in the container 1, the position of the liquid level, and the like can be calculated as necessary.

If it is confirmed from the detection signal from the pressure gauge 6 that a predetermined amount or more of liquid has been injected into the liquid reservoir 1a of the container 1, the control device drives the pump of the suction nozzle 2 and The liquid in the liquid reservoir 1a is sucked by a predetermined amount while lowering 2. The liquid sucked by the suction nozzle 2 is supplied to a predetermined location such as an analysis unit for analyzing the liquid. As a result, the amount of liquid in the liquid reservoir 1a decreases, and the pressure detected by the pressure gauge 6 decreases accordingly. Thereafter, the control device controls the solenoid valve 4 to make the input port 4i communicate with the normally closed port 4c, and moves the cylinder 7a of the pump 7 backward. Thereby, the liquid in the liquid reservoir 1a flows into the drain pipe 3, and is sucked by the pump 7 through the filter 5 and the electromagnetic valve 4. When the liquid in the liquid reservoir 1a of the container 1 is completely sucked by the pump 7,
The inside of the drain pipe 3 between the container 1 and the solenoid valve 4 is at atmospheric pressure. Thereafter, the control device controls the solenoid valve 4 to make the input port 4i communicate with the normally open port 4o, and advances the cylinder 7a of the pump 7. As a result, the liquid in the pump 7, that is, the excess liquid, is discharged to a predetermined place such as a drain bottle (not shown) through the solenoid valve 4 and the drain pipe 3.

FIG. 2 is an explanatory diagram for explaining a change in pressure detected by the pressure gauge 6 in the above operation. The horizontal axis represents time, and the vertical axis represents detected pressure. When starting the injection of liquid into the liquid reservoir portion 1a of the container 1 at time t _1, the drain pipe 3
The internal pressure, ie, the detected pressure, gradually increases. Liquid reservoir 1
When a predetermined amount or more of liquid is terminated injected at time t _2, which is injected into the a, the pressure at that point is maintained. When starting the suction of the liquid from the liquid reservoir portion 1a at time t _3, the detected pressure decreases gradually. When the liquid in the liquid reservoir portion 1a terminates the aspiration at time t ₄ when being predetermined suction amount, the pressure at that point is maintained. When the solenoid valve 4 and the input port 4i and normally closed port 4c to retract the piston 7a of the pump 7 with switching to a state that communicates at time t _5, the liquid i.e. the excess liquid in the liquid reservoir portion 1a through the drain pipe 3 The detected pressure fluctuates on the negative pressure side. Time t when all the excess liquid in the liquid reservoir 1a is sucked by the pump 7.
_{At step 6} , the solenoid valve 4 is switched to a state where the input port 4i and the normally open port 4o communicate with each other.
When a is advanced, the excess liquid in the pump 7 is discharged to a drain bottle (not shown) or the like. In this case, the detected pressure is back to the same atmospheric pressure as the time t ₁ earlier.

By the way, if the clogging in the filter 5 has occurred, as shown in FIG. 3, when starting the suction of excess liquid by the pump 7 at time t _5, the sensed pressure between the positive pressure and the negative pressure It fluctuates, and in the case of a negative pressure, it is slightly lower than the atmospheric pressure. Therefore, the excess liquid in the liquid reservoir 1a is hardly sucked into the pump 7. And Stopping the suction by the pump 7 at time t _6, since between the filter 5 and the electromagnetic valve 4 of the drain pipe 3 is left in the negative pressure, the fluctuation of the sensed pressure is continued. After time t ₇ in which the fluctuation of the sensed pressure has subsided, the detected pressure corresponding to the amount of excess liquid remaining in the liquid reservoir portion 1a is maintained. The detected pressure is only slightly lower than the detected pressure from time t ₄ to time t _5.

When the liquid leaks from the drain pipe 3 or the solenoid valve 4, as shown in FIG.
Not rise until the detected pressure at a predetermined pressure by injecting a liquid into the liquid reservoir portion 1a from time t ₁ to time t _2, the the detected pressure stops injection of the liquid at time t ₂ is reduced gradually.

[0029] Thus, by detecting the pressure at time t ₂ is raised to a predetermined pressure in the liquid reservoir portion 1a can know that a predetermined amount or more of liquid is injected, the detected pressure at time t ₆ is By returning to the atmospheric pressure, it is possible to know that all the surplus liquid in the liquid reservoir 1a has been discharged. Of course, the difference between the detected pressure between the time t ₃ and time t _4, a predetermined amount of liquid can be known that it has been sucked from the liquid reservoir portion 1a. Further, it is known that the filter 5 is clogged because the detected pressure does not become sufficiently negative when the excess liquid is sucked by the pump 7 and the fluctuation of the detected pressure continues even after the operation of the pump 7 is stopped. be able to. Further, since the detected pressure does not change at all when the surplus liquid is sucked by the pump 7, it is possible to know the failure of the pump 7 or the solenoid valve 4. That is, in this case, it can be assumed that the pump 7 has stopped or the solenoid valve 4 has not been switched. Further, if the detected pressure at the time t ₂ remains at the atmospheric pressure or is extremely lower than the predetermined pressure, it is determined that the liquid has not been injected from the suction nozzle 2 or that a large leak has occurred in the drain pipe 3. You can know. Further, when the liquid is not injected and sucked by the suction nozzle 2 and the suction is not performed by the pump 7, the detected pressure gradually decreases, so that a small leakage to the drain pipe 3 or the solenoid valve 4 is caused. Can be known that has occurred.

Therefore, by monitoring the detection signal from the pressure gauge 6 by the control device, the occurrence of the abnormality can be notified and the cause of the abnormality can be displayed on the display screen.

FIG. 5 is a schematic block diagram of a main part of an automatic blood test apparatus using the above-mentioned liquid amount detecting apparatus. This automatic blood test apparatus uses a high-performance liquid chromatography for diluting test liquids in dilution tanks 11 and 12. Sample loop 1 of the injection valve 13 of the device
The sample liquid is supplied to the sample No. 4 and analyzed by separating the test liquid in a column (not shown).

That is, a test liquid obtained by diluting the blood to be tested with a diluent is injected into the diluting tank 11 by a tube pump 15, and the test liquid in the diluting tank 11 is suctioned by the tube pump 15. The test liquid is returned to the dilution tank 11 through a path passing through the nozzle 16, the tube pump 15, the solenoid valves 17, 18, 19, 20, the sample loop 14, and the solenoid valves 21, 22, and 23. The test solution is filled, the injection valve 13 is switched, and the test solution in the sample loop 14 is supplied to the column. For example, about 900 microliters of a test liquid is injected into the dilution tank 11, of which about 5 microliters is blood and the remaining about 895 microliters is diluent. Further, of these test liquids of about 900 microliters, about 25 microliters are supplied to the sample loop 14.

When the test liquid in the sample loop 14 is supplied to the column, the solenoid valve 25 is switched, and the pump 26
Is driven, and the cleaning liquid in the cleaning liquid bottle 27 is pumped.
6, the electromagnetic valve 25 is switched, the pump 26 discharges the cleaning liquid, and the pump 26, the electromagnetic valves 25, 2
The cleaning liquid is supplied into the dilution tank 11 through a path passing through the sample loop 14, the sample loop 14, and the solenoid valves 21, 22, 23, and the test liquid remaining in the path is cleaned. Further, the electromagnetic valve 20 is switched, and the pump 26, the electromagnetic valves 25, 20, 19, 18,
The cleaning liquid is supplied into the dilution tank 11 through a path passing through the tube pump 15, the tube pump 15, and the suction nozzle 16, and the test liquid remaining in the path is cleaned.

Then, the suction nozzle 16 moves to the dilution tank 12 side, and the solenoid valve 23 is switched, so that the test liquid in the dilution tank 12 is removed from the sample loop 14 as in the case of the dilution tank 11.
Supplied to

On the other hand, while the test liquid in the dilution tank 12 is being supplied to the sample loop 14, the solenoid valve 28 is switched, and the residual test liquid in the dilution tank 11, that is, the excess liquid and the cleaning liquid are diluted. Pump 32 passes through the path of tank 11, filter 29, solenoid valve 30, three-way joint 31, and solenoid valve 28.
Is sucked. Further, the electromagnetic valve 28 is switched, and the surplus liquid and the cleaning liquid discharged from the pump 32 are stored in the drain bottle 33.

Of course, the path of the test liquid on the dilution tank 12 side is also washed with the cleaning liquid, similarly to the path of the test liquid on the dilution tank 11 side.

As described above, the test liquid in the dilution tank 11 and the test liquid in the dilution tank 12 are alternately supplied to the sample loop 14, and the paths of the test liquid are alternately washed. The test liquid can be inspected efficiently.

In FIG. 5, reference numeral 34 denotes a filter;
Reference numeral 6 denotes an electromagnetic valve, reference numerals 38 and 39 denote pressure gauges, and an electromagnetic valve 36 as a switching valve and the three-way joint 31
9 or for communicating the inside of the drain pipe between the filter 34 and the solenoid valve 28 to the atmosphere. In other words, when the filter 29 or the filter 34 is clogged, the suction in the pump 32 causes a negative pressure in the drain pipe between the filter 29 or the filter 34 and the solenoid valve 28, and the dilution tank 11 or the dilution tank 12
This prevents excessive liquid or cleaning liquid remaining in the drain pipe between the filter 29 and the filter 29 or the filter 34 from gradually leaking into the drain pipe between the filter 29 or the filter 34 and the solenoid valve 28. The solenoid valve 22
This is for making the path of the test liquid communicate with the atmosphere as needed.

Thus, the dilution tanks 11 and 12 correspond to the container 1 of FIG. 1, the suction nozzle 16 corresponds to the suction nozzle 2 of FIG. 1, and the pressure gauges 38 and 39 correspond to the pressure gauge 6 of FIG. And
The filters 29 and 34 correspond to the filter 5 in FIG. 1, the solenoid valve 28 corresponds to the solenoid valve 4 in FIG. 1, and the pump 32 corresponds to the pump 7 in FIG. Based on the signal, the amount and level of the test liquid in the dilution tanks 11 and 12, clogging of the filters 29 and 34, the pump 32
The malfunction of the solenoid valve 28 and the leakage of the drain pipe and the like are detected by a control device (not shown).

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a liquid amount detection device according to the present invention.

FIG. 2 is an explanatory diagram illustrating a change in detected pressure in a normal state detected by a pressure gauge provided in the liquid amount detection device according to the present invention.

FIG. 3 is an explanatory diagram illustrating a change in detected pressure in a clogged state of a filter, which is detected by a pressure gauge provided in a liquid amount detection device according to the present invention.

FIG. 4 is an explanatory diagram illustrating a change in detected pressure in a leak state of a drain pipe detected by a pressure gauge provided in a liquid amount detection device according to the present invention.

FIG. 5 is a schematic configuration diagram of a main part of an automatic blood test apparatus using the liquid amount detection device according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 container 3 drain pipe 4 solenoid valve 5 filter 6 pressure gauge 7 pump 36 solenoid valve

Claims (5)

[Claims] 1. A liquid amount detecting device for detecting a liquid amount of a liquid in a container capable of discharging an excess liquid through a drain pipe by a pump, wherein a liquid amount in the drain pipe is provided between the container and the pump. Characterized by comprising pressure detection means for detecting pressure,
Liquid level detector. 2. The liquid according to claim 1, wherein the drain pipe is capable of communicating with the pump via an electromagnetic switching valve, and is closed by the electromagnetic switching valve when not communicating with the pump. Quantity detection device. 3. The liquid amount detecting device according to claim 1, wherein the pressure detecting means has a pressure sensor that outputs a signal of a voltage corresponding to a pressure in the drain pipe. 4. The drain pipe is provided with a filter for removing impurities at an appropriate position between the container and the pump, and the pressure detecting means includes a drain between the container and the filter. The liquid amount detecting device according to claim 1, wherein the device detects a pressure in a pipe. 5. The drain pipe is provided with a switching valve between the filter and the pump, the switching valve being capable of communicating the inside of the drain pipe with the atmosphere.
3. The liquid amount detection device according to 1.