JP2014111202A - Device for transporting liquid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a bubble generated in a liquid in a flow pipe.SOLUTION: A device for transporting a liquid includes: a pump for supplying a liquid to the outside of the device; a flow pipe which is connected to the pump, and through which the liquid flows; an electrode pair provided in the flow pipe; and a detector for detecting a bubble in the flow pipe on the basis of a change of a capacitance of the electrode pair.

Description

  The present invention relates to a liquid transport apparatus.

In order to maintain homeostasis of blood glucose level and to alleviate pain, a medication pump that delivers a drug solution subcutaneously has been developed. For example, a continuous subcutaneous infusion pump is used to administer insulin to type 1 diabetic patients. Some continuous subcutaneous infusion pumps have a function of executing a program for performing basal administration for supplementing basal secretion and batch additional administration for supplementing additional secretion according to the life pattern of the patient.
In such a pump, even if the pump is operating normally, the gas dissolved in the chemical solution appears as bubbles, and the bubbles may hinder the transport of the chemical solution.
Patent Document 1 discloses that bubbles are detected by ultrasonic waves.

JP-A-11-332982

Generation | occurrence | production of a bubble will absorb the pulsation of the pressure which pushes out a chemical | medical solution from a pump. As a result, the drug solution may not be appropriately administered subcutaneously or the like. Therefore, it is desirable to detect bubbles generated in the liquid in the flow tube so that such a situation does not occur.
This invention is made | formed in view of such a situation, and it aims at detecting the bubble which has arisen in the liquid in a flow tube.

The main invention for achieving the above object is:
A liquid transport device,
A pump for supplying liquid to the outside of the liquid transport device;
A flow tube connected to the pump and through which the liquid flows;
An electrode pair provided inside the flow tube;
A detection unit for detecting bubbles in the flow tube based on a change in capacitance of the electrode pair;
With
A capacitive element is connected in series to the electrode pair, and a DC voltage is applied to the electrode pair and the capacitive element,
A change in capacitance of the electrode pair is a liquid transport device that is detected based on a change in voltage divided by the capacitive element.

  Other features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

FIG. 1A is an explanatory diagram of the chemical solution transport apparatus 1 according to the present embodiment, and FIG. 1B is a diagram illustrating the relationship of each element in the chemical solution transport apparatus 1. It is a figure explaining the abnormality detection part 7 and the bubble detection part 8 of chemical | medical solution transport. It is a figure explaining the capacity | capacitance partial pressure of a capacitor | condenser. It is a figure explaining other arrangement | positioning of the electrode pair. FIG. 5A is a diagram illustrating a state in which electrodes are provided in close contact with the tube, and FIG. 5B is a diagram illustrating a state in which electrode pairs are provided on the outer surface of the tube. 6A is a first diagram illustrating a first method for detecting bubble size, FIG. 6B is a second diagram illustrating a first method for detecting bubble size, and FIG. FIG. 5 is a diagram showing the relationship between the voltage V of the reference capacitor and the bubble area ratio k. FIG. 7A is a first diagram illustrating a second method for detecting the bubble size, and FIG. 7B is a second diagram illustrating a second method for detecting the bubble size. These are the 3rd figures explaining the 2nd method of detecting the size of a bubble. FIG. 8A is a fourth diagram for explaining a second method for detecting the bubble size, and FIG. 8B is a fifth diagram for explaining the second method for detecting the bubble size. It is a 6th figure explaining the 2nd method of detecting the size of a bubble. It is a figure which shows the relationship of each element when the reference electrode is arrange | positioned in a reservoir. It is a figure explaining the electrode pair attachment 81b. It is a figure explaining the press member which presses the site | part in which the electrode pair was provided.

  At least the following matters will become clear from the description of the present specification and the accompanying drawings.

A liquid transport device,
A pump for supplying liquid to the outside of the liquid transport device;
A flow tube connected to the pump and through which the liquid flows;
An electrode pair provided inside the flow tube;
A detection unit for detecting bubbles in the flow tube based on a change in capacitance of the electrode pair;
A liquid transport device comprising:
By doing in this way, the bubble which has arisen in the liquid in a flow tube is detectable.

In such a liquid transport apparatus, a capacitive element is connected to the electrode pair, a DC voltage is applied to the electrode pair and the capacitive element, and a capacitance change of the electrode pair is distributed to the capacitive element. It is desirable that the detection is performed based on a change in the pressed voltage, that is, a change in voltage between the electrode pair and the connection terminal of the capacitor element. At this time, the electrode pair and the capacitive element are preferably connected in series.
By doing in this way, generation | occurrence | production of the bubble which arose in the flow tube is detectable based on the change of the voltage divided by the capacitive element.

The electrode pair is preferably provided in close contact with the inner wall of the flow tube.
By doing so, it is possible to detect the generation of bubbles with higher sensitivity than when the electrode pair is provided on the outer wall of the flow tube.

Further, it is desirable that the size of the detected bubble is estimated based on the capacitance of the electrode pair.
In this way, not only the generation of bubbles but also the size thereof can be estimated.

In addition, it is preferable that three or more pairs of electrode pairs are provided in the flow tube, and the size of bubbles in the flow tube is obtained based on a change in capacitance of each of the three or more electrode pairs.
In this way, when bubbles are moving through three or more pairs of electrodes, the size of the bubbles can be estimated based on the change in capacitance of these three or more pairs of electrodes. .

The flow tube is preferably composed of a plurality of detachable tubes provided with the electrode pair.
In this way, a plurality of electrode pairs can be easily provided.

Moreover, it is desirable that a member for pressing a portion where the electrode pair is provided from the outside of the tube is provided on the tube.
By doing in this way, the space | interval of an electrode pair can be maintained constant in the site | part in which the electrode pair was provided.

Further, it is preferable that a reservoir for storing the liquid is provided, and the capacitive element is an electrode pair provided in the reservoir.
By doing so, it is possible to detect in advance the liquid in the reservoir.

=== Embodiment ===
The chemical solution transport device 1 as a liquid transport device in the present embodiment is used, for example, to administer a chemical solution subcutaneously to a human body or to administer a chemical solution to an animal during an animal experiment.

  FIG. 1A is an explanatory diagram of the chemical transport device 1 in the present embodiment. FIG. 1B is a diagram showing the relationship of each element in the chemical solution transport apparatus 1. Hereinafter, the outline of the chemical transport device 1 will be described with reference to these drawings.

  The chemical transport apparatus 1 includes a reservoir 3, a flow tube 4 (a tube 71a and a tube 81a to be described later are included in this), a micropump 5, a motor 5a for driving the micropump 5, and an abnormality detection of the chemical transport Unit 7, bubble detection unit 8, control circuit 9 for controlling them, and battery 11 for supplying power.

  Among these, the reservoir 3, the motor 5a, the control circuit 9, and the battery 11 constitute a main unit. The micro pump 5, the flow tube 4, the chemical solution transport abnormality detection unit 7, and the bubble detection unit 8 constitute a sub unit connected to the main unit described above. The sub unit can be removed from the main unit and replaced.

  As shown in FIG. 1A, a chemical transport device 1 is formed so as to protrude substantially at the center upper side, and an injection port 2 through which a chemical solution is injected from the outside into the chemical transport device 1, and the chemical transport device 1 as a whole arranged next to the left. A reservoir 3 in which the drug solution is stored inside by communicating with the injection port 2, an elastic flow tube 4 communicating with the reservoir 3 and conducting the drug solution, and a drug solution transporting device 1. A micropump 5 that is disposed on the substantially right half side of the whole and is configured near the substantially central portion of the flow tube 4 is disposed. Further, the chemical transport apparatus 1 includes a chemical transport abnormality detection unit 7 and a bubble detection unit 8. Further, on the back surface of the chemical solution transport device 1, a control circuit 9 including an integrated circuit (IC) and other electronic components including a drive circuit for the micropump 5 and a control circuit for controlling the drive circuit, and a battery 11 (oxidation) Silver battery) is arranged. Further, the rear end of the flow tube 4 is configured to project outward from the right end portion of the drug solution transport apparatus 1 and to be connected to a catheter that supplies the drug solution into the body.

  The injection port 2 communicates with the reservoir 3, and the chemical liquid can be stored in the reservoir 3 by injecting the chemical liquid into the injection port 2 with an injection needle or the like. The reservoir 3 communicates with the flow pipe 4. In the flow tube 4, a predetermined phenomenon can be detected by an abnormality detection unit 7 and a bubble detection unit 8 for transporting a chemical solution, which will be described later. Further, the micropump 5 is in contact with the flow tube 4, and the micropump 5 is controlled so that the drug solution can be injected into the body while adjusting the dose.

  The micropump 5 includes a cam portion 5 b and a plurality of pressing pins 5 c that press the flow pipe 4. In the chemical transport apparatus 1, a flow tube frame 14 fixed in contact with the flow tube 4 is provided as shown in the figure. As the motor 5a rotates clockwise, the cam portion 5b of the micropump 5 is also rotated clockwise. And the cam part 5b presses sequentially from the left side press pin 5c to the right side press pin 5c, and pushes out the chemical | medical solution from the upstream of the flow tube 4 to the downstream. With such a configuration, the drug solution can be fed into the body relatively slowly without causing large fluctuations.

  In such a chemical solution transport apparatus 1, for example, when bubbles are generated in the flow tube or clogging occurs, there arises a problem that the chemical solution is not administered into the body. Therefore, in this embodiment, the abnormality detection part 7 and the bubble detection part 8 of chemical | medical solution transport as shown below are provided.

FIG. 2 is a diagram illustrating the abnormality detection unit 7 and the bubble detection unit 8 for transporting chemicals.
The abnormality detector 7 for transporting chemical liquid includes a tube 71a having a closed end 73a, a free movement plug 72a, and an optical sensor 75a for detecting the position of the free movement plug 72a. The free movement stopper 72a is provided so as to be in close contact with the inside of the pipe 71a, but can be freely moved within the pipe 71a by applying an external force. The free movement stopper 72a is made of a material that is difficult to deform, is inactive (insoluble) with respect to a liquid such as a chemical solution, and has a low frictional resistance.

  In the figure, since the chemical solution flows from the pump side, the chemical solution is filled on the pump side of the free movement stopper 72a. On the other hand, a gas 74a is sealed between the free movement stopper 72a and the closed end 73a. The gas 74a is, for example, nitrogen gas, but is not limited to this as long as it is harmless to the human body. It is also desirable that the gas be insoluble.

  The optical sensor 75 a is connected to the control circuit 9. When the optical sensor 75 reads the barcode printed on the surface of the free movement stopper, the control circuit 9 can grasp the position of the free movement stopper 72a.

  The figure also includes a compensation tube 71b used for temperature compensation, a compensation free movement plug 72b, and an optical sensor 75b for detecting the position of the compensation free movement plug 72b. The compensating tube 71b has the same dimensions as the portion of the tube 71a described above. Moreover, the dimension of the compensation free movement stopper 72b is the same as that of the above-mentioned free movement stopper 72a. The compensation pipe 71b is also provided with a closed end 73b, and the same gas 74b as the gas 74a is sealed between the closed end 73b and the compensation free moving plug 72b. On the other hand, the other end 76 of the closed end 73b of the compensating tube 71b is released to the atmosphere.

  The same amount of gas is sealed in the tube 71a and the compensation tube 71b. For example, when the compensation free moving plug 72b moves by Δlt due to a temperature change, it is considered that the enthalpy proportional to Δlt increases when the sealing gas is inactive and there is no change in internal energy. Therefore, assuming that the enthalpy of the gas sealed in the free-moving plug 72a has also increased by the same amount, by using a correction formula that uses the amount of movement Δlt, errors due to temperature changes are removed, and abnormalities in chemical transport are detected. Will be able to. Assuming that the cross-sectional area of the compensating free movement stopper is the same as that of the free movement stopper, the correction equation is p = k · p0 (l0 + Δlt) / (l1 + Δl) (where p is the flow path pressure (= sealing gas) Pressure), p0 is the atmospheric pressure, l0 is the position of the compensation free moving stopper before the temperature change, l1 is the position of the free moving stopper before the temperature change), and k is the correction coefficient).

  The bubble detection unit 8 includes an electrode pair 82 (including an electrode 82a and an electrode 82b) in a tube 81. The electrode pair 82 is connected to the control circuit 9 via connection lines 83a and 83b. In one embodiment, the electrode pair 82 is formed inside the tube 81, and the connection lines 83 a and 83 b are drawn out to the outside through a part of the tube 81 and connected to the control circuit 9.

  In the control circuit 9, a reference capacitor (not shown) is connected in series with the electrode pair. A predetermined voltage is applied to both ends of the reference capacitor and electrode pair 82 connected in series. Normally, a chemical solution should be filled between the electrode pair 82, but when bubbles are generated, the bubbles enter between the electrode pair 82. Then, the capacitance of the electrode pair 82 changes before and after the generation of bubbles. When the capacitance changes, the voltage at the connection terminal between the electrode pair and the reference capacitor also changes. Therefore, based on the change in the voltage across the reference capacitor, the control circuit 9 can determine whether or not bubbles have occurred.

  FIG. 3 is a diagram for explaining the capacitance partial pressure of the capacitor. In the figure, the capacitance Cm of the electrode pair 82 is shown. The electrostatic capacity Cm is an electrostatic capacity in a state where the electrode pair 82 is completely immersed in the chemical solution. Further, the capacitance Cref of the reference capacitor 91 connected to the electrode pair 82 is shown. The capacitance of the reference capacitor in the present embodiment is approximately the same as the capacitance Cm, but is not limited to this.

  Here, the voltage Vcc is applied to the electrode pair 82 and the reference capacitor 91 connected in series, and the voltage applied to the reference capacitor 91 is indicated by V. Here, in a state where the electrode pair 82 is completely immersed in the chemical solution, the voltage applied to the reference capacitor 91 is divided equally to the voltage applied to the electrode pair 82 and becomes Vcc / 2. .

  However, when air bubbles enter between the electrode pair 82, assuming that the dielectric constant in the air is about 1 and the dielectric constant of the chemical solution is εm, Vcc / (εm + 1). Here, when Vcc is 1 (V) and the dielectric constant εm of the chemical solution is approximated by the dielectric constant 80 of water, the voltage V applied to the reference capacitor 91 when the electrode pair 82 is immersed in the chemical solution is Although it is 0.5 (V), it is 0.012 (V) when the chemical solution between the electrodes of the electrode pair is excluded by bubbles.

  In the present embodiment, the voltage divided by the reference capacitor 91 is detected in this way, and it is determined whether or not bubbles are generated based on the change in the voltage. The reference capacitor 91 is provided in the control circuit 9, and the control circuit 9 detects whether or not bubbles are generated based on a change in voltage.

  FIG. 4 is a diagram illustrating another arrangement of the electrode pair 82. The figure shows a state in which the tube 84 is connected to the tube 81 via the tube connection pipe 86. The tube 84 is attached to the outside of the chemical solution transport apparatus 1. An injection needle 85 is further attached to the tip of the tube 84. In the above-described embodiment, the electrode pair 82 is provided in the tube 81, but the electrode pair 82 may be provided in a tube 84 connected to the tube 81 as shown in FIG.

  FIG. 5A is a diagram illustrating a state in which an electrode is provided in close contact with the tube. The figure shows a state in which the electrode pair 82 is formed in close contact with the inner wall surface of the tube 81. As described above, since the electrode pair 82 is brought into close contact with the inner wall surface of the tube 81, the bubbles do not wrap around the back side between the electrodes, so that the generation of the bubbles can be detected more accurately. .

  As a method for bringing the electrode pair 82 into close contact with the inner wall surface in this way, a method of plating a metal on the inner wall surface of the tube 81 may be used. Specifically, the metal may be plated by a technique such as electroless plating. Further, the connection lines 83 a and 83 b connected to the electrode pair 82 may be formed by plating the inner wall surface in the same manner as the electrode pair 82. By doing so, there is an advantage that the electrode pair 82 and the connection lines 83a and 83b can be formed simultaneously.

  FIG. 5B is a diagram illustrating a state in which electrode pairs are provided on the outer surface of the tube. The figure shows a state in which the electrodes 82 a and 82 b of the electrode pair 82 are provided so as to be in close contact with the outer wall surface of the tube 81. Thus, by providing the electrode pair 82 on the outer wall surface of the tube 81, the electrode pair can be easily provided on the tube 81. Also in this case, since the bubbles do not go around to the back side between the electrodes, the generation of the bubbles can be accurately detected. In this case, in order to keep the voltage change to be measured large, it is desirable to select the material of the tube wall where the electrode pair is provided with a dielectric constant as large as possible and to reduce the wall thickness as much as possible.

  FIG. 6A is a first diagram illustrating a first method of detecting the bubble size. In the figure, an electrode pair 82 provided inside the tube 81 and bubbles air generated between the electrodes are shown. Here, the bubble air is generated so as to occupy a part between the electrodes. A part between the electrodes not occupied by the bubbles is filled with a chemical solution. Thus, in the case where the air between the electrodes is not filled with the air bubble, the size of the air bubble can be estimated as follows.

FIG. 6B is a second diagram illustrating a first method of detecting the bubble size. This figure is an equivalent circuit of the electrode pair 82 where the air bubble is sandwiched and the portion filled with the chemical solution. In the figure, it is shown that the parallel connection of the capacitance Cair at the location where the bubble air is sandwiched and the capacitance Cm '' at the location where the chemical solution is sandwiched replaces Cm in FIG. . The equivalent capacitance of the parallel connection of the capacitance can be obtained by the sum of these two capacitances. Here, assuming that the area ratio occupied by the bubbles between the electrode pairs is k, the equivalent capacitance Cm ′ of the electrode pairs is Vcc = 1.
Cm ′ = k · Cair + (1−k) Cm
It is.
At this time, the voltage V applied to the reference capacitor 91 in FIG. 3 is εair = 1.
V = Cm ′ / (Cm ′ + Cref)
= (K + (1-k) εm) / (k + (2-k) εm)
Is approximated by Therefore,
k = (2V-1) εm / ((1-V) · (1-εm))
Thus, by measuring the voltage V of the reference capacitor, the area ratio k occupied by the bubbles between the electrode pairs can be known.

  FIG. 6C is a diagram illustrating the relationship between the voltage V of the reference capacitor and the area ratio k of the bubbles. This figure illustrates the relationship of the above equation. Thus, by measuring the voltage V applied to the reference capacitor, it is possible to know the area ratio k at which bubbles between electrode pairs are closed.

  FIG. 7A is a first diagram illustrating a second method for detecting the bubble size, and FIG. 7B is a second diagram illustrating a second method for detecting the bubble size. These are the 3rd figures explaining the 2nd method of detecting the size of a bubble. These drawings show that the first electrode pair 821, the second electrode pair 822, and the third electrode pair 833 are provided in the tube 81. Each electrode pair is connected to a reference capacitor in the same manner as described above. Moreover, as time series, it arranges in order of FIG. 7A to FIG. 7C.

  In FIG. 7A, a bubble air is generated between the electrodes of the first electrode pair 821. On the other hand, the gap between the second electrode pair 822 and the third electrode pair 823 is filled with a chemical solution. At this time, the voltage of the reference capacitor connected to the first electrode pair 821 is the voltage of the reference capacitor connected to the second electrode pair 822 and the voltage of the reference capacitor connected to the third electrode pair 823. It can be confirmed that the voltage is extremely lower than the voltage, and thus it is possible to detect that bubbles are generated in the first electrode pair 821.

  In FIG. 7B, bubbles air are generated between the electrodes of the second electrode pair 822. On the other hand, the gap between the first electrode pair 821 and the third electrode pair 823 is filled with a chemical solution. At this time, the voltage of the reference capacitor connected to the second electrode pair 822 is the voltage of the reference capacitor connected to the first electrode pair 821 and the voltage of the reference capacitor connected to the third electrode pair 823. It can be confirmed that the voltage is extremely lower than the voltage, and thus it is possible to detect that bubbles are generated in the second electrode pair 822.

  In FIG. 7C, bubbles air are generated between the electrodes of the third electrode pair 823. On the other hand, the gap between the first electrode pair 821 and the second electrode pair 822 is filled with a chemical solution. At this time, the voltage of the reference capacitor connected to the third electrode pair 823 is the voltage of the reference capacitor connected to the first electrode pair 821 and the voltage of the reference capacitor connected to the second electrode pair 822. It can be confirmed that the voltage is extremely lower than the voltage, and thus it is possible to detect that bubbles are generated in the third electrode pair 823.

  When the voltage of the reference capacitor is changed in the patterns as shown in FIGS. 7A to 7C, it can be estimated that the size of the bubble is almost equal to the size of the electrode of the electrode pair.

  FIG. 8A is a fourth diagram for explaining a second method for detecting the bubble size, and FIG. 8B is a fifth diagram for explaining the second method for detecting the bubble size.

  In FIG. 8A, bubbles air are generated between the electrodes of the first electrode pair 821 and the second electrode pair 822. On the other hand, the gap between the electrodes of the third electrode pair 823 is filled with a chemical solution. At this time, the voltage of the reference capacitor connected to the first electrode pair 821 and the voltage of the reference capacitor connected to the second electrode pair 822 are the same as those of the reference capacitor connected to the third electrode pair 823. It can be confirmed that the voltage is extremely lower than the voltage, whereby it is possible to detect that bubbles are generated in the first electrode pair 821 and the second electrode pair 822.

  In FIG. 8B, bubbles air are generated between the electrodes of the second electrode pair 822 and the third electrode pair 823. On the other hand, the gap between the electrodes of the first electrode pair 821 is filled with a chemical solution. At this time, the voltage of the reference capacitor connected to the second electrode pair 822 and the voltage of the reference capacitor connected to the third electrode pair 823 are the same as those of the reference capacitor connected to the first electrode pair 821. It can be confirmed that the voltage is extremely lower than the voltage, whereby it is possible to detect that bubbles are generated in the second electrode pair 822 and the third electrode pair 823.

  When the voltage of the reference capacitor is changed in the patterns as shown in FIGS. 8A to 8C, the size of the bubble is approximately equal to the size from one electrode pair to another adjacent electrode pair. Can be estimated.

  FIG. 9 is a sixth diagram illustrating a second method of detecting the bubble size. Since a discussion similar to that described above is established, even when a bubble that straddles three electrode pairs is generated in this way, it is possible to estimate the size by increasing the number of electrode pairs. it can.

  FIG. 10 is a diagram illustrating the relationship between the elements when the reference electrode pair is disposed in the reservoir. In the above-described embodiment, the reference capacitor 91 is provided. Here, the same electrode pair 92 (reference electrode pair 92) as the electrode pair 82 provided in the tube 81 is provided in the reservoir. . The electrostatic capacity of the reference electrode pair 92 at this time is the same as the electrostatic capacity of the electrode pair 82.

  By providing the reference electrode pair 92 inside the reservoir 3, if the chemical solution in the reservoir 3 runs out, the voltage of the electrode pair 81 in the tube 81 decreases with respect to the reference electrode pair 92. By doing so, it becomes possible to detect the lack of the chemical solution in the reservoir.

  Further, since these are immersed in the same type of liquid, the electrostatic capacity of the reference electrode pair 92 immersed in the liquid of the reservoir 3 is reduced by the electrostatic capacity of the electrode pair 82 immersed in the liquid of the tube 81. It becomes the same as the capacity. Therefore, there is an advantage that the capacitance of the reference electrode pair 92 can be automatically adjusted to be the same as the capacitance of the tube 81 according to the dielectric constant of the chemical solution.

  FIG. 11 is a diagram for explaining the electrode pair attachment 81b. An electrode pair 82 is formed on the inner wall of the electrode pair attachment 81b. Moreover, the process which can be connected to another tube is made | formed at the both ends of the electrode pair attachment 81b. By doing in this way, as above-mentioned, even if it is a case where a several electrode pair is required in order to estimate the size of a bubble, the electrode pair 82 can be increased easily.

  FIG. 12 is a diagram illustrating a pressing member that presses a portion where an electrode pair is provided. In the figure, the arrangement of the electrode pair 82 in the tube 81 and the cross section of the tube 81 at the position where the electrode pair 82 is arranged are shown.

  When the tube 81 is an elastic body, the tube 81 may be crushed or the distance between the electrodes of the electrode pair 82 may be changed, which may adversely affect the above-described detection. Therefore, it is good also as providing the fixing member 85 for fixing the distance of an electrode tube in the site | part where the electrode is arrange | positioned so that such a thing may not arise. The fixing member 85 has a “U” shape and is made of a material such as metal that is difficult to be deformed even when an external force is applied.

  According to the method described above, it is possible to appropriately detect bubbles generated in the liquid in the flow tube.

  The above-described embodiments are for facilitating the understanding of the present invention, and are not intended to limit the present invention. The present invention can be changed and improved without departing from the gist thereof, and it is needless to say that the present invention includes equivalents thereof.

1 chemical transport device, 2 injection port, 3 reservoir, 4 flow tube,
5 Micro pump, 5a motor, 5b cam part, 5c pressing pin,
7 anomaly detector, 71a tube, 72a free-moving stopper, 73a closed end,
71b Compensation tube, 72b Compensation free moving stopper, 73b Closed end,
74a gas, 75a light sensor, 74b gas, 75b light sensor,
8 Bubble detection unit, 81 tube, 82 electrode pair, 86 tube connection pipe 9 control circuit, 91 reference capacitor,
10 exterior case, 11 battery, 12 reservoir frame, 14 flow tube frame

The main invention for achieving the above object is:
A liquid transport device,
A pump for supplying liquid to the outside of the liquid transport device;
A flow tube connected to the pump and through which the liquid flows;
An electrode pair provided outside the flow tube;
A detection unit for detecting bubbles in the flow tube based on a change in capacitance of the electrode pair;
With
A capacitive element is connected in series to the electrode pair, and a DC voltage is applied to the electrode pair and the capacitive element,
A change in capacitance of the electrode pair is a liquid transport device that is detected based on a change in voltage divided by the capacitive element.

Claims (7)

A liquid transport device,
A pump for supplying liquid to the outside of the liquid transport device;
A flow tube connected to the pump and through which the liquid flows;
An electrode pair provided inside the flow tube;
A detection unit for detecting bubbles in the flow tube based on a change in capacitance of the electrode pair;
With
A capacitive element is connected in series to the electrode pair, and a DC voltage is applied to the electrode pair and the capacitive element,
A liquid transport device in which a change in capacitance of the electrode pair is detected based on a change in voltage divided by the capacitive element. A reservoir for storing the liquid;
The liquid transport apparatus according to claim 1, wherein the capacitive element is an electrode pair provided in the reservoir.   The liquid transport apparatus according to claim 1, wherein the electrode pair is provided in close contact with an inner wall of the flow tube.   The liquid transport device according to claim 1, wherein the size of the detected bubble is estimated based on the capacitance of the electrode pair. Three or more pairs of the electrode pairs are provided in the flow tube,
The liquid transport device according to any one of claims 1 to 3, wherein a size of a bubble in the flow tube is obtained based on a change in capacitance of each of the three or more electrode pairs.   The liquid transport apparatus according to any one of claims 1 to 5, wherein the flow tube includes a plurality of detachable tubes provided with the electrode pair.   The liquid transport apparatus according to any one of claims 1 to 6, wherein a member for pressing a portion where the electrode pair is provided from the outside of the tube is provided in the tube.

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