Bubble detector and liquid feeding pump

Abstract

To provide a bubble detector and a liquid feeding pump capable of detecting bubbles in a tube body using an electrode in not direct contact with liquid in the tube body, with a structure that is hardly influenced by foreign matter adhesion and simple.SOLUTION: A bubble detector comprises: a plurality of electrodes that can be arranged on an external surface of a tube body inside which a flow path through which liquid can flow is partitioned, at different positions in upstream / downstream directions of the flow path; a voltage application unit capable of applying AC voltage between any two electrodes adjacent in the upstream / downstream directions of the plurality of electrodes; and a controlling unit that on the basis of the existence of electric conduction between the two electrodes, detects the existence of bubbles in a detection section between the two electrodes of the tube body.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to an air bubble detection device and a liquid delivery pump. [Background technology]

[0002] Conventionally, there has been known a bubble detection device capable of detecting bubbles mixed in a liquid such as a medicinal liquid in a pipe. Patent Document 1 discloses a liquid transport device as this type of bubble detection device. The liquid transport device described in Patent Document 1 includes an electrode pair provided inside a flow pipe and a detection unit that detects bubbles in the flow pipe based on a change in capacitance of the electrode pair. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-174394 A Summary of the Invention [Problem to be solved by the invention]

[0004] It is preferable that the detection of air bubbles in a tubular body can be performed using a versatile tubular body such as an infusion tube for delivering a liquid such as a medicinal solution to a living body, and from the viewpoint of preventing infection, the detection can be performed without directly contacting the liquid such as a medicinal solution in the tubular body. On the other hand, when detecting air bubbles in the tubular body from outside the tubular body, the detection accuracy of the air bubbles may be reduced due to the influence of foreign matter such as the medicinal solution adhering to the outer surface of the tubular body.

[0005] Furthermore, as for air bubble detection devices, there are configurations that detect the presence or absence of air bubbles using ultrasonic waves, in addition to a configuration that electrically detects the presence or absence of air bubbles using electrodes as in Patent Document 1. However, air bubble detection devices that use ultrasonic waves still have room for improvement in terms of simplifying the device configuration for air bubble detection.

[0006] The present disclosure has been made in consideration of these problems, and aims to provide an air bubble detection device and a liquid delivery pump that are capable of detecting air bubbles inside a tube using electrodes that do not directly contact the liquid inside the tube, are less susceptible to the effects of foreign matter adhesion, and have a simple configuration. [Means for solving the problem]

[0007] The air bubble detection device according to the first aspect of the present disclosure comprises: (1) a plurality of electrodes that can be arranged on an outer surface of a tube that defines a flow path through which a liquid can flow, and that can be arranged at different positions in the upstream and downstream directions of the flow path; a voltage application unit capable of applying an AC voltage between any two electrodes adjacent to each other in the upstream / downstream direction among the plurality of electrodes; and a control unit that detects the presence or absence of bubbles in the detection section between the two electrodes in the upstream and downstream directions of the pipe based on the presence or absence of electrical current between the two electrodes.

[0008] According to one embodiment of the present disclosure, an air bubble detection device includes: (2) The control unit is a bubble detection device described in (1) above, in which, when there is no current flow between at least one set of two electrodes adjacent to each other in the upstream / downstream direction among the multiple electrodes, the control unit estimates the bubble volume based on the non-current flow time in the detection section between the at least one set of two electrodes.

[0009] According to one embodiment of the present disclosure, an air bubble detection device includes: (3) the plurality of electrodes includes three or more electrodes forming two or more of the detection zones therebetween; The air bubble detection device according to (1) or (2) above, wherein the control unit estimates the air bubble volume based on combined information on the presence or absence of current flow in each of the two or more detection sections.

[0010] According to one embodiment of the present disclosure, an air bubble detection device includes: (4) The air bubble detection device according to (2) or (3) above further comprises an alarm unit that issues an external alarm when the air bubble volume estimated by the control unit is equal to or greater than a predetermined threshold value.

[0011] According to one embodiment of the present disclosure, an air bubble detection device includes: (5) the plurality of electrodes includes three or more electrodes forming two or more of the detection zones therebetween; The control unit is a bubble detection device described in any one of (1) to (4) above, which estimates the presence or absence of foreign matter adhering to the outer surface of the tubular body based on time history information on the presence or absence of current flow in each of the two or more detection sections.

[0012] A liquid feed pump according to a second aspect of the present disclosure includes: (6) A liquid delivery pump including the air bubble detection device according to any one of (1) to (5) above.

[0013] A liquid feed pump according to one embodiment of the present disclosure includes: (7) a liquid delivery section that is disposed on a downstream side of the flow path in the upstream / downstream direction with respect to the plurality of electrodes of the bubble detection device and is capable of delivering the liquid in the tubular body; The liquid delivery pump according to (6) above, further comprising: a clamping portion that is adapted to clamp the tubular body and abuts against an outer surface of the tubular body at a position between the plurality of electrodes of the bubble detection device in the upstream / downstream direction. Effect of the Invention

[0014] According to the present disclosure, it is possible to provide an air bubble detection device and a liquid delivery pump that can detect air bubbles in a tubular body using electrodes that do not directly contact the liquid in the tubular body, are less susceptible to the effects of foreign matter adhesion, and have a simple configuration. [Brief description of the drawings]

[0015] [Figure 1] FIG. 2 is a diagram showing an air bubble detection device according to an embodiment of the present disclosure, illustrating a state in which no air bubbles are present in the detection section of the flow path. [Diagram 2] 2 is a diagram showing a state in which an air bubble is present in a detection section of a flow path in the air bubble detection device shown in FIG. 1. [Diagram 3] 2 is a diagram showing the state of air bubbles passing through a detection section of a flow path and the time history of the presence or absence of electrical current flow between an upstream electrode and a downstream electrode in the air bubble detection device shown in FIG. 1. FIG. [Figure 4A] FIG. 13 is a diagram showing an example of a method for estimating bubble volume using three or more electrodes, showing a state in which bubbles having a bubble volume less than a predetermined threshold are circulating. [Figure 4B] FIG. 4B is a diagram similar to FIG. 4A, illustrating a state in which air bubbles having a volume equal to or greater than a predetermined threshold value are circulating. [Figure 5A] FIG. 13 is a diagram showing another example of a method for estimating bubble volume using three or more electrodes, showing a state in which bubbles having a bubble volume less than a predetermined threshold value are circulating. [Figure 5B] FIG. 5B is a diagram similar to FIG. 5A, illustrating a state in which air bubbles having a volume equal to or greater than a predetermined threshold value are circulating. [Figure 6A] FIG. 13 is a diagram showing the time history of the presence or absence of current flow in the upstream detection section and the downstream detection section when no foreign matter is attached to the outer surface of the pipe body. [Figure 6B] FIG. 13 is a diagram showing the time history of the presence or absence of current flow in the upstream detection section and the downstream detection section when a foreign object is attached to the outer surface of the tube so as to be in contact with both the upstream electrode and the central electrode. [Figure 6C] FIG. 13 is a diagram showing the time history of the presence or absence of current flow in the upstream detection section and the downstream detection section when a foreign object is attached to the outer surface of the tube so as to be in contact with both the central electrode and the downstream electrode. [Figure 7] FIG. 2 is a diagram showing an example of the external configuration of an infusion pump, and is a front view of the infusion pump with a door portion closed relative to a main body portion. [Figure 8] 8 is a front view of the infusion pump shown in FIG. 7 with the door portion open relative to the main body portion. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, an embodiment of an air bubble detection device and a liquid feed pump according to the present disclosure will be described with reference to the drawings. In each drawing, the same components are denoted by the same reference numerals.

[0017] 1 and 2 are diagrams showing an air bubble detection device 1 as one embodiment of the air bubble detection device according to the present disclosure. As shown in Fig. 1 and 2, the air bubble detection device 1 is attached to a tubular body 50 that defines a flow path 50a through which a liquid X, such as a medical solution, can flow when used. However, the air bubble detection device according to the present disclosure may also be provided with a mounting part to which the tubular body 50 can be attached, and the tubular body 50 may be attached to the mounting part of the air bubble detection device.

[0018] The air bubble detection device 1 of the present embodiment is used in a medical application for detecting air bubbles mixed in liquid X, such as a medicinal liquid, administered to a living body, but is not limited to this application. The air bubble detection device according to the present disclosure can detect air bubbles mixed in any liquid X in the tubular body 50, and is not limited to use in medical applications.

[0019] For ease of explanation, the direction from the upstream side to the downstream side of the flow path 50a in the tubular body 50 and the direction from the downstream side to the upstream side of the flow path will hereinafter be referred to as the "upstream / downstream direction A".

[0020] 1 and 2, the air bubble detection device 1 includes a sensor unit 1a and a control unit 4. The sensor unit 1a includes a plurality of electrodes 2 and a voltage application unit 3.

[0021] The multiple electrodes 2 can be arranged at different positions in the upstream / downstream direction A on the outer surface of the tube 50. That is, each of the multiple electrodes 2 is arranged to abut on a different position in the upstream / downstream direction A on the outer surface of the tube 50. In FIG. 1 and FIG. 2, two electrodes 2a and 2b are shown as the multiple electrodes 2. However, the number of the multiple electrodes 2 is not limited to two in this embodiment. Hereinafter, for convenience of explanation, the electrode 2a located on the upstream side of the flow path among the two electrodes 2a and 2b in this embodiment will be referred to as the "upstream electrode 2a". In addition, the electrode 2b located on the downstream side of the flow path among the two electrodes 2a and 2b in this embodiment will be referred to as the "downstream electrode 2b". Furthermore, when there is no particular distinction between the upstream electrode 2a and the downstream electrode 2b, they will be simply referred to as the "electrode 2".

[0022] The electrode 2 may be, for example, an electrode made of a conductive metal. As shown in Fig. 1 and Fig. 2, the upstream electrode 2a and the downstream electrode 2b of this embodiment surround the outer surface of the tube 50 and contact the outer surface of the tube 50 over the entire circumferential area, but this is not limited to the configuration. The upstream electrode 2a and the downstream electrode 2b may contact only a portion of the outer surface of the tube 50 in the circumferential direction.

[0023] The voltage application unit 3 can apply an AC voltage between any two of the multiple electrodes 2 that are adjacent to each other in the upstream / downstream direction A. The voltage application unit 3 of this embodiment can apply an AC voltage between the upstream electrode 2a and the downstream electrode 2b. More specifically, the voltage application unit 3 may be, for example, an AC power source 3a. The AC power source 3a as the voltage application unit 3 is electrically connected to the upstream electrode 2a and the downstream electrode 2b by conductors 10a and 10b, respectively. The voltage application unit 3 can apply an AC voltage of a predetermined frequency or higher, such as 100 kHz or higher, between the upstream electrode 2a and the downstream electrode 2b.

[0024] When an AC voltage is applied between the upstream electrode 2a and the downstream electrode 2b in contact with the outer surface of the tube 50, the upstream electrode 2a and the downstream electrode 2b are electrically connected to the liquid X in the flow path 50a in the tube 50, even if the tube 50 itself is made of resin and has no electrical conductivity. This is because the peripheral wall of the tube 50 sandwiched between the upstream electrode 2a and the downstream electrode 2b and the liquid X in the flow path 50a functions as a capacitor component, and the impedance of the peripheral wall of the tube 50 is reduced by the high-frequency AC voltage. Therefore, in the detection section N between the two electrodes 2 in the upstream / downstream direction A of the tube 50, when no air bubbles Y are contained in the liquid X, the two electrodes 2 conduct electricity through the liquid X. That is, in this embodiment, in the detection section N between the upstream electrode 2a and the downstream electrode 2b, when no air bubbles Y are contained in the liquid X, the upstream electrode 2a and the downstream electrode 2b conduct electricity through the liquid X. Conversely, when air bubbles Y are contained in the liquid X in the detection section N between the upstream electrode 2a and the downstream electrode 2b, the upstream electrode 2a and the downstream electrode 2b do not conduct electricity through the liquid X. Fig. 1 shows a state in which no air bubbles Y are contained in the liquid X in the flow path 50a in the detection section N between the upstream electrode 2a and the downstream electrode 2b. In contrast, Fig. 2 shows a state in which air bubbles Y are contained in the liquid X in the flow path 50a in the detection section N between the upstream electrode 2a and the downstream electrode 2b.

[0025] The control unit 4 can detect the presence or absence of bubbles Y in the detection section N between the two electrodes 2 in the upstream / downstream direction A of the tube 50 based on the presence or absence of current flow between the two electrodes 2. That is, the control unit 4 of this embodiment can detect the presence or absence of bubbles Y in the detection section N between the upstream electrode 2a and the downstream electrode 2b in the upstream / downstream direction A of the tube 50 based on the presence or absence of current flow between the upstream electrode 2a and the downstream electrode 2b. More specifically, the control unit 4 of this embodiment can detect that no bubbles Y are present in the detection section N by detecting that current is flowing between the upstream electrode 2a and the downstream electrode 2b in the state shown in FIG. 1. Conversely, the control unit 4 of this embodiment can detect that no bubbles Y are present in the detection section N by detecting that no current is flowing between the upstream electrode 2a and the downstream electrode 2b in the state shown in FIG. 2.

[0026] The control unit 4 includes a processor, such as a general-purpose processor, such as a CPU (central processing unit) or an MPU (Micro Processing Unit), or a dedicated processor specialized for a specific process. The control unit 4 may be, for example, a microcontroller. The control unit 4 executes processes related to the operation of the bubble detection device 1 while controlling each part of the bubble detection device 1. Specifically, the control unit 4 may control the operation of the AC power source 3a as the voltage application unit 3. The control unit 4 may also control the notification unit 5, which will be described later, to notify the outside of the detection result of the presence or absence of the bubble Y. The control unit 4 may further include a storage unit, such as a ROM (read only memory) or a RAM (random access memory).

[0027] As described above, the air bubble detection device 1 can detect air bubbles Y in the tubular body 50 with a simple configuration by using the electrode 2 that does not directly contact the liquid X in the tubular body 50 and utilizing the presence or absence of electrical current.

[0028] In addition, since the two electrodes 2 adjacent in the upstream / downstream direction A are disposed at a distance in the upstream / downstream direction A, even if a foreign matter Z such as a chemical solution (see FIG. 6B and FIG. 6C) is attached to the outer surface of the tubular body 50, the possibility that the foreign matter Z will come into contact with the two adjacent electrodes 2 at the same time can be reduced compared to the case where the air bubbles Y are detected at only one point in the upstream / downstream direction A. That is, it is possible to prevent current from passing between the two adjacent electrodes 2 through the foreign matter Z. In other words, it is possible to prevent the foreign matter Z from becoming a detour for current flow between the two adjacent electrodes 2, and it is possible to prevent a decrease in the detection accuracy of the air bubbles Y due to the attachment of the foreign matter Z. That is, it is possible to reduce the influence of the attachment of the foreign matter Z.

[0029] As shown in FIGS. 1 and 2, the air bubble detection device 1 of this embodiment includes a notification unit 5 in addition to the sensor unit 1a and control unit 4 described above.

[0030] The notification unit 5 can, for example, notify the outside of the detection result of the presence or absence of the air bubble Y. The notification unit 5 can be, for example, a display unit such as a liquid crystal display. The display unit as the notification unit 5 can notify the detection result of the presence or absence of the air bubble Y by displaying, for example, characters, symbols, etc. Furthermore, the notification unit 5 is not limited to a display unit, and can be, for example, a speaker that can notify the outside by sound. Furthermore, the notification unit 5 can be, for example, an indicator that can notify the outside by light. In this way, the configuration of the notification unit 5 is not particularly limited as long as it is configured to notify the outside of the detection of the presence or absence of the air bubble Y.

[0031] Furthermore, the notification unit 5 may notify other information to the outside in addition to or instead of the detection result of the presence or absence of the air bubble Y. The notification unit 5 may notify the detection result of the presence or absence of the air bubble Y to the outside only when, for example, the volume of the air bubble Y (hereinafter, referred to as "air bubble volume") described below, estimated by the control unit 4, is equal to or greater than a predetermined threshold value (see FIGS. 4A to 5B). The notification unit 5 may notify the outside of the presence or absence of a foreign object Z described below, estimated by the control unit 4, for example (see FIGS. 6A to 6C).

[0032] The air bubble detection device 1 may further include other components in addition to the above-described sensor unit 1a, control unit 4, and notification unit 5. The air bubble detection device 1 may further include, for example, an information input unit 6, a time measurement unit 7, etc., which will be described later.

[0033] Next, the estimation of bubble volume by the bubble detection device 1 of this embodiment will be described with reference to Fig. 3. Fig. 3 is a diagram showing the state of a bubble Y passing through a detection section N and the time history of the presence or absence of electrical current flow between the upstream electrode 2a and the downstream electrode 2b.

[0034] As shown in Figure 3, the control unit 4 of this embodiment can estimate the bubble volume based on the non-current flow time T1 in the detection section N between at least one set of two electrodes 2 adjacent to each other in the upstream / downstream direction A among the multiple electrodes 2.

[0035] More specifically, the control unit 4 of this embodiment can estimate the bubble volume based on the non-energization time T1 in the detection section N between the upstream electrode 2a and the downstream electrode 2b when no current is passed between a pair of the upstream electrode 2a and the downstream electrode 2b adjacent to each other in the upstream / downstream direction A. Here, the "non-energization time T1" refers to the duration of one non-energization state.

[0036] The bubble detection device 1 of this embodiment includes an information input unit 6 capable of acquiring flow rate information (liquid delivery speed information) of the liquid X flowing through the flow path 50a of the tubular body 50. The information input unit 6 may be capable of receiving the flow rate information of the liquid X flowing through the flow path 50a from an external device such as an external computer via wired or wireless communication. The information input unit 6 may also be an operation unit such as a touch panel that allows a medical professional to manually input the flow rate information. The information input unit 6 outputs the acquired flow rate information to the control unit 4.

[0037] The bubble detection device 1 of this embodiment also includes a time measurement unit 7. The time measurement unit 7 may be a known configuration such as a clock. The control unit 4 acquires from the time measurement unit 7 the time ts at which the bubble Y enters the detection section N and the state between the upstream electrode 2a and the downstream electrode 2b changes from a conducting state to a non-conducting state, and the time te at which the bubble Y completely passes through the detection section N and the state between the upstream electrode 2a and the downstream electrode 2b changes from a non-conducting state back to a conducting state. The control unit 4 of this embodiment can calculate the non-conducting time T1 from the acquired times ts and te.

[0038] The control unit 4 of this embodiment can calculate the distance L1 traveled by the bubble Y during the non-power time T1 based on the flow rate information acquired from the information input unit 6 and the non-power time T1 calculated from the time information acquired from the time measurement unit 7.

[0039] Moreover, the length L2 of the detection section N is stored in advance as known information in, for example, a storage unit.

[0040] Therefore, the control unit 4 of this embodiment can calculate the length L3 of the bubble Y in the upstream / downstream direction A by subtracting the length L2 of the detection section N from the distance L1 calculated as described above. Furthermore, the control unit 4 of this embodiment can calculate the bubble volume based on the calculated length L3 of the bubble Y in the upstream / downstream direction A and the flow path diameter D1 of the tubular body 50 that is stored in advance in, for example, a memory unit.

[0041] In this manner, the control unit 4 of the present embodiment can estimate the bubble volume based on the non-energization time T1 in the detection section N between the upstream electrode 2a and the downstream electrode 2b.

[0042] The control unit 4 may be configured to control the notification unit 5 to notify the presence of the bubbles Y to the outside only when the estimated bubble volume is equal to or greater than a predetermined threshold. In other words, the control unit 4 may be configured not to notify the presence of the bubbles Y to the outside when the estimated bubble volume is less than a predetermined threshold. Depending on the use of the bubble detection device 1, if the bubble volume is sufficiently small, the influence of the bubbles Y may be negligible. Therefore, the control unit 4 may estimate the bubble volume, and if the estimated bubble volume is less than a predetermined threshold, the control unit 4 may not notify the presence of the bubbles Y to the outside. In addition, the control unit 4 may use three or more electrodes 2, estimate the bubble volume multiple times, calculate the average value of the bubble volume, compare the average value of the bubble volume with a predetermined threshold, and notify the presence of the bubbles Y only when the average value of the bubble volume is equal to or greater than the predetermined threshold. This can improve the accuracy of estimating the bubble volume.

[0043] Although Fig. 3 shows an example in which the bubble volume is estimated using the non-energization time T1, the bubble volume may be estimated by other methods. Figs. 4A to 5B are diagrams showing an example in which the control unit 4 estimates the bubble volume using three or more electrodes 2 without using the non-energization time T1.

[0044] 4A to 5B, the bubble detection device 1 includes, as the plurality of electrodes 2, three or more electrodes 2 that form two or more detection zones N between each other. Note that Figs. 4A to 5B show the movement of only one bubble Y from the upstream side of the flow channel to the downstream side of the flow channel.

[0045] More specifically, the bubble detection device 1 shown in Figs. 4A and 4B includes three electrodes 2c, 2d, and 2e that form two detection zones N between them. Hereinafter, for convenience of explanation, the electrode 2c located most upstream in the flow path among the three electrodes 2c, 2d, and 2e shown in Figs. 4A and 4B is referred to as the "upstream electrode 2c". Furthermore, the electrode 2e located most downstream in the flow path among the three electrodes 2c, 2d, and 2e shown in Figs. 4A and 4B is referred to as the "downstream electrode 2e". Furthermore, the electrode 2d located in the middle in the upstream / downstream direction A among the three electrodes 2c, 2d, and 2e shown in Figs. 4A and 4B is referred to as the "center electrode 2d". Furthermore, the detection zone N between the upstream electrode 2c and the center electrode 2d is referred to as the "upstream detection zone N1", and the detection zone N between the center electrode 2d and the downstream electrode 2e is referred to as the "downstream detection zone N2". In addition, when there is no particular distinction between the upstream electrode 2c, the central electrode 2d, and the downstream electrode 2e, they will simply be referred to as "electrodes 2." Furthermore, when there is no particular distinction between the upstream detection section N1 and the downstream detection section N2, they will simply be referred to as "detection section N."

[0046] The control unit 4 shown in Figures 4A and 4B can estimate the bubble volume based on the combined information on the presence or absence of current flow in each of two or more detection sections N. Specifically, the control unit 4 shown in Figures 4A and 4B can estimate the bubble volume based on the combined information on the presence or absence of current flow in each of the upstream detection section N1 and the downstream detection section N2. More specifically, the control unit 4 shown in Figures 4A and 4B can estimate whether the bubble volume is equal to or greater than a predetermined threshold value based on the combined information on the presence or absence of current flow in each of the upstream detection section N1 and the downstream detection section N2.

[0047] In the example shown in Fig. 4A and Fig. 4B, the contact length L4 of one electrode 2 other than the two electrodes 2 located at both ends among the multiple electrodes 2 is used to estimate the bubble volume. The contact length L4 is the length in the upstream / downstream direction A of the contact area where the electrode 2 contacts the outer surface of the tube 50. As described above, in the example shown in Fig. 4A and Fig. 4B, the upstream electrode 2c, the central electrode 2d, and the downstream electrode 2e are provided as the multiple electrodes 2. That is, in the example shown in Fig. 4A and Fig. 4B, the contact length L4 of the central electrode 2d can be used to estimate the bubble volume.

[0048] Specifically, in the examples shown in Figures 4A and 4B, the contact length L4 of the central electrode 2d is set as the threshold value L5 of the length L3 of the bubble Y for estimating the bubble volume. As described above, the length L3 of the bubble Y is the length of the bubble Y in the upstream / downstream direction A. That is, Figure 4A shows an example in which the length L3 of the bubble Y is less than the contact length L4 of the central electrode 2d. Figure 4B shows an example in which the length L3 of the bubble Y is equal to or greater than the contact length L4 of the central electrode 2d.

[0049] 4A, the length L3 of the bubble Y is less than the contact length L4 of the central electrode 2d, i.e., less than the threshold value L5, so that when the bubble Y passes the position of the central electrode 2d from the upstream side of the flow path to the downstream side of the flow path, the upstream detection section N1 and the downstream detection section N2 do not simultaneously become non-conductive. In other words, at least one of the upstream detection section N1 and the downstream detection section N2 is in a conductive state.

[0050] Conversely, in Figure 4B, the length L3 of the bubble Y is greater than or equal to the contact length L4 of the central electrode 2d, i.e., greater than or equal to the threshold value L5, so that when the bubble Y passes the position of the central electrode 2d from the upstream side of the flow path to the downstream side of the flow path, the upstream detection section N1 and the downstream detection section N2 simultaneously become non-conductive.

[0051] In other words, when the control unit 4 shown in Figures 4A and 4B detects that the upstream detection section N1 and the downstream detection section N2 are simultaneously in a non-energized state, it estimates that the length L3 of the bubble Y is greater than or equal to the threshold value L5, i.e., the bubble volume is greater than or equal to a predetermined threshold value.

[0052] Conversely, the control unit 4 shown in Figures 4A and 4B estimates that the length L3 of the bubble Y is less than the threshold value L5, i.e., the bubble volume is less than a predetermined threshold value, unless it detects that the upstream detection section N1 and the downstream detection section N2 are simultaneously in a non-energized state.

[0053] In this way, the control unit 4 shown in Figures 4A and 4B can estimate whether the bubble volume is equal to or greater than a predetermined threshold without using the non-current-flow time T1 between two adjacent electrodes 2.

[0054] Next, with reference to Figures 5A and 5B, an example different from Figures 4A and 4B will be described, in which the bubble volume is estimated without using the non-energization time T1 by using three or more electrodes 2. The example shown in Figures 5A and 5B differs from the example shown in Figures 4A and 4B mainly in that the threshold value L5 of the length L3 of the bubble Y is set to a value longer than the contact length L4 of the electrode 2.

[0055] Specifically, the bubble detection device 1 shown in FIG. 5A and FIG. 5B includes five electrodes 2f, 2g, 2h, 2i, and 2j that form four detection zones N between them. Hereinafter, for convenience of explanation, the five electrodes 2f, 2g, 2h, 2i, and 2j shown in FIG. 5A and FIG. 5B are referred to as the "first electrode 2f," the "second electrode 2g," the "third electrode 2h," the "fourth electrode 2i," and the "fifth electrode 2j" in order from the electrode 2f located at the most upstream side of the flow path to the electrode 2j located at the most downstream side of the flow path. In addition, the detection zone N between the first electrode 2f and the second electrode 2g is referred to as the "first detection zone N3." The detection zone N between the second electrode 2g and the third electrode 2h is referred to as the "second detection zone N4." The detection zone N between the third electrode 2h and the fourth electrode 2i is referred to as the "third detection zone N5." The detection section N between the fourth electrode 2i and the fifth electrode 2j is referred to as the "fourth detection section N6." When the first to fifth electrodes 2f to 2j are not particularly distinguished from each other, they are simply referred to as the "electrodes 2." When the first to fourth detection sections N3 to N6 are not particularly distinguished from each other, they are simply referred to as the "detection section N."

[0056] The control unit 4 shown in Figures 5A and 5B can estimate the bubble volume based on the combined information on the presence or absence of current flow in each of two or more detection sections N. Specifically, the control unit 4 shown in Figures 5A and 5B can estimate the bubble volume based on the combined information on the presence or absence of current flow in each of the first to fourth detection sections N3 to N6. More specifically, the control unit 4 shown in Figures 5A and 5B can estimate whether the bubble volume is equal to or greater than a predetermined threshold value based on the combined information on the presence or absence of current flow in each of the first to fourth detection sections N3 to N6.

[0057] In the example shown in FIG. 5A and FIG. 5B, unlike the example shown in FIG. 4A and FIG. 4B described above, the contact length L4 of one electrode 2 other than the two electrodes 2 located at both ends among the multiple electrodes 2 is not used as the threshold value L5 of the length L3 of the bubble Y for estimating the bubble volume. That is, in FIG. 5A and FIG. 5B, the threshold value L5 of the length L3 of the bubble Y is set to a value longer than the contact length L4 of the electrode 2. In this way, when the threshold value L5 of the length L3 of the bubble Y is longer than the contact length L4 of the electrode 2, the method shown in FIG. 4A and FIG. 4B cannot estimate whether the bubble volume is equal to or greater than a predetermined threshold. Therefore, in the example shown in FIG. 5A and FIG. 5B, the bubble volume is estimated based on the number of sections in which the current is not applied simultaneously among the first to fourth detection sections N3 to N6 when the bubble Y passes the position of the reference electrode 2 (the third electrode 2h in FIG. 5A and FIG. 5B) from the upstream side of the flow path to the downstream side of the flow path. In other words, in the example shown in FIGS. 5A and 5B, the value of threshold L5 is set so that the number of sections in which the current is not applied simultaneously varies when bubble Y passes the position of third electrode 2h.

[0058] Specifically, in the examples shown in Figures 5A and 5B, when the bubble Y passes the position of the third electrode 2h from the upstream side of the flow path to the downstream side of the flow path, the bubble volume is estimated based on whether or not all of the first to fourth detection sections N3 to N6 are simultaneously in a non-energized state. Figure 5A shows an example in which the length L3 of the bubble Y is less than the threshold value L5. Figure 5B shows an example in which the length L3 of the bubble Y is equal to or greater than the threshold value L5.

[0059] 5A, the length L3 of the bubble Y is less than the threshold value L5, so when the bubble Y passes the position of the third electrode 2h from the upstream side to the downstream side of the flow path, all of the first to fourth detection zones N3 to N6 do not simultaneously become non-conductive. In other words, at least one of the first detection zone N3 and the fourth detection zone N6 is in a conductive state.

[0060] Conversely, in Figure 5B, since the length L3 of the bubble Y is greater than or equal to the threshold value L5, when the bubble Y passes the position of the third electrode 2h from the upstream side of the flow path to the downstream side of the flow path, all of the first to fourth detection sections N3 to N6 simultaneously become non-conductive.

[0061] In other words, when the control unit 4 shown in Figures 5A and 5B detects that all of the first to fourth detection sections N3 to N6 are simultaneously in a non-energized state, it estimates that the length L3 of the bubble Y is greater than or equal to the threshold value L5, i.e., the bubble volume is greater than or equal to a predetermined threshold value.

[0062] Conversely, when the control unit 4 shown in Figures 5A and 5B does not detect that all of the first to fourth detection sections N3 to N6 are simultaneously in a non-energized state, it estimates that the length L3 of the bubble Y is less than the threshold value L5, i.e., the bubble volume is less than a predetermined threshold value.

[0063] In this way, according to the control unit 4 shown in Figures 5A and 5B, it is possible to estimate whether the bubble volume is equal to or greater than a predetermined threshold without using the non-current-flow time T1 between two adjacent electrodes 2.

[0064] 4A to 5B, a method for estimating whether or not the bubble volume is equal to or greater than a predetermined threshold without using the non-energization time T1 between two adjacent electrodes 2 has been described, but the method for estimating whether or not the bubble volume is equal to or greater than a predetermined threshold without using the non-energization time T1 between two adjacent electrodes 2 is not limited to the specific method shown in Fig. 4A and Fig. 4B or the specific method shown in Fig. 5A and Fig. 5B. The contact length L4 of the electrodes 2, the length L2 of the detection section N, the number of electrodes 2, the threshold value L5 of the length L3 of the bubble Y, and the like may be set as appropriate.

[0065] 6A to 6C show an example in which the presence or absence of a foreign object Z adhering to the outer surface of a tubular body 50 is estimated using three electrodes 2. For convenience of explanation, in FIGS. 6A to 6C, the upstream electrode 2c, the central electrode 2d, and the downstream electrode 2e shown in FIGS. 4A and 4B are used as the three electrodes 2, but the electrodes are not limited to the upstream electrode 2c, the central electrode 2d, and the downstream electrode 2e as long as they form two or more detection zones N between each other. For example, the first to fifth electrodes 2f to 2j forming the first to fourth detection zones N3 to N6 shown in FIGS. 5A and 5B may be used.

[0066] 6A to 6C each show the state of a bubble Y passing through the upstream detection section N1 and the downstream detection section N2, the time history of whether or not current is applied in the upstream detection section N1, and the time history of whether or not current is applied in the downstream detection section N2.

[0067] Fig. 6A shows a time history of the presence or absence of current flow in the upstream detection section N1 and the downstream detection section N2 when no foreign matter Z is attached to the outer surface of the tubular body 50. As shown in Fig. 6A, when an air bubble Y moves from the upstream side of the flow path to the downstream side of the flow path, first, the upstream detection section N1 changes from a current-carrying state to a non-current-carrying state, and then the downstream detection section N2 changes from a current-carrying state to a non-current-carrying state.

[0068] In contrast, Figures 6B and 6C show time histories of the presence or absence of current flow in the upstream detection section N1 and the downstream detection section N2 when a foreign object Z is attached to the outer surface of the tube 50. Figure 6B shows a state in which a foreign object Z is attached to the outer surface of the tube 50 so as to contact both the upstream electrode 2c and the central electrode 2d. Figure 6C shows a state in which a foreign object Z is attached to the outer surface of the tube 50 so as to contact both the central electrode 2d and the downstream electrode 2e.

[0069] 6B, when there is a foreign object Z in contact with both the upstream electrode 2c and the central electrode 2d, even if a bubble Y moves from the upstream side of the flow path to the downstream side of the flow path and enters the upstream detection section N1, the upstream detection section N1 does not change from an energized state to a non-energized state. This is because the foreign object Z acts as a detour, and the state between the upstream electrode 2c and the central electrode 2d is maintained in an energized state. Then, when the bubble Y moves further from the upstream side of the flow path to the downstream side of the flow path, the downstream detection section N2 changes from an energized state to a non-energized state.

[0070] 6C, when a foreign object Z is present in contact with both the central electrode 2d and the downstream electrode 2e, and an air bubble Y moves from the upstream side of the flow path to the downstream side of the flow path and enters the upstream detection section N1, the upstream detection section N1 changes from an energized state to a non-energized state. Even if the air bubble Y further moves from the upstream side of the flow path to the downstream side of the flow path and enters the downstream detection section N2, the downstream detection section N2 does not change from an energized state to a non-energized state. This is because the foreign object Z becomes a detour, and an energized state is maintained between the central electrode 2d and the downstream electrode 2e.

[0071] Therefore, the control unit 4 can estimate the presence or absence of foreign matter Z adhering to the outer surface of the tubular body 50 based on the time history information on the presence or absence of current flow in each of two or more detection sections N. More specifically, in the example shown in Figures 6A to 6C, the control unit 4 can estimate the presence or absence of foreign matter Z adhering to the outer surface of the tubular body 50 based on the time history information on the presence or absence of current flow in each of the upstream detection section N1 and the downstream detection section N2.

[0072] Specifically, as shown in FIG. 6A, the control unit 4 estimates that no foreign object Z is present on the outer surface of the tube 50 when a state change from an energized state to a non-energized state in the upstream detection section N1, and a state change from an energized state to a non-energized state in the downstream detection section N2 occur sequentially.

[0073] In response to this, as shown in FIG. 6B, when a state change from an energized state to a non-energized state does not occur in the upstream detection section N1 but a state change from an energized state to a non-energized state occurs in the downstream detection section N2, the control unit 4 estimates that a foreign object Z is present on the outer surface of the tube body 50 in the upstream detection section N1.

[0074] Furthermore, as shown in Fig. 6C, if the state does not change from the energized state to the non-energized state in the downstream detection section N2 even after a predetermined time has elapsed since the state changed from the energized state to the non-energized state in the upstream detection section N1, the control section 4 estimates that a foreign object Z is present on the outer surface of the pipe 50 in the downstream detection section N2. The above-mentioned "predetermined time" can be set by the control section 4 based on information such as flow rate information acquired from the above-mentioned information input section 6 or the like.

[0075] In this manner, the control unit 4 can estimate the presence or absence of a foreign matter Z adhering to the outer surface of the tubular body 50 based on the time history information on the presence or absence of current flow in each of two or more detection sections N.

[0076] 7 and 8 are diagrams showing an infusion pump 100 including the above-described air bubble detection device 1, which is one embodiment of the infusion pump of the present disclosure.

[0077] First, an overview of the infusion pump 100 will be described.

[0078] FIG. 7 is a diagram showing an example of the external configuration of the infusion pump 100. FIG. 7 is a front view of the infusion pump 100 with the door 110 closed on the main body 200 (see FIG. 8). The infusion pump 100 shown in FIG. 7 shows a state in which the infusion tube 160 is installed as the tubular body 50. FIG. 8 is a front view of the infusion pump 100 with the door 110 open on the main body 200. Therefore, in FIG. 8, the front of the main body 200 and the back of the door 110 are exposed. The infusion pump 100 shown in FIG. 8 shows a state in which the infusion tube 160 is not installed.

[0079] For ease of explanation, the state in which the door part 110 is closed relative to the main body part 200 (see FIG. 7) will be simply referred to as the "closed state." Also, for ease of explanation, the state in which the door part 110 is not closed relative to the main body part 200 (for example, the state shown in FIG. 8) will be simply referred to as the "open state."

[0080] As shown in FIG. 7, the infusion pump 100 is provided with an infusion tube 160 as the tube body 50. The infusion pump 100 can push the infusion tube 160 to send the liquid in the infusion tube 160. Details will be described later, but in the infusion pump 100 of this embodiment, the door part 110 is opened and the infusion tube 160 is placed at a predetermined position of the main body part 200, and the door part 110 is closed to install the infusion tube 160 in the infusion pump 100. In other words, the infusion pump 100 with the door part 110 in the closed state shown in FIG. 7 defines a linear hollow part in which the infusion tube 160 is installed, and the infusion tube 160 is arranged in this hollow part. An infusion bag 161 containing a liquid such as a predetermined liquid medicine is connected to the upstream side of the flow path of the infusion tube 160 (the opposite direction to the liquid sending direction) of the infusion tube 160 relative to the part of the infusion tube 160 installed in the infusion pump 100. Furthermore, a clamp member 162 and an indwelling catheter 163 are connected to the downstream side of the flow path (in the direction of liquid delivery) of the infusion tube 160 relative to the portion of the infusion tube 160 that is installed in the infusion pump 100. The indwelling catheter 163 is left in a state of being inserted into a vein or the like of the patient. By using the infusion pump 100, the flow rate (liquid delivery speed) and the like of the liquid in the infusion tube 160 per unit time can be controlled. Therefore, the amount of liquid in the infusion bag 161 administered to the patient per unit time and the like can be controlled by the infusion pump 100.

[0081] As shown in FIGS. 7 and 8, the infusion pump 100 includes a main body 200 and a door 110 attached to the main body 200 so as to be openable and closable.

[0082] 7, a display unit 120 that displays various information, an operation unit 130 in which operation switches are arranged, and a door lock lever 140 are arranged on the front surface of the door unit 110. In addition, an operation indicator 150 is arranged on the upper surface of the door unit 110.

[0083] The display unit 120 is provided with a flow rate display unit 121 which switches between the set value and actual value of the infusion rate, a planned volume / accumulated volume display unit 122 which switches between the planned volume and accumulated volume, an alarm display unit 123 which displays various alarm information, and an occlusion pressure setting display unit 124 which displays the set level of the occlusion pressure of the infusion tube 160 as "L", "M", or "H".

[0084] The alarm display unit 123 further includes an air bubble detection display unit 125 that turns on when the air bubble detection sensor 21 (see FIG. 8) serving as the air bubble detection device 1 described above detects air bubbles in the infusion tube 160, and a battery voltage drop display unit 126 that turns on when the voltage of the built-in battery of the infusion pump 100 drops. The alarm display unit 123 further includes an occlusion abnormality display unit 127 that turns on when the occlusion pressure of the infusion tube 160 reaches a set level, a door open state display unit 128 that turns on when the door unit 110 is in an open state, and a completion display unit 129 that turns on when the infusion is completed.

[0085] The operation unit 130 is equipped with an up / down switch 131 for setting the infusion rate and planned amount, a fast-forward switch 132 that enables infusion at a rate higher than the set infusion rate (mL / h) while it is pressed, a start switch 134 that starts infusion when pressed, a stop switch 133 that forcibly stops infusion when pressed, and a power switch 135 for turning the power of the main body unit 200 on / off.

[0086] Adjacent to the power switch 135 are a power lamp 136 that lights up when a commercial power source or a DC power source is used, and a battery lamp 137 that lights up when the built-in battery is charging and indicates the remaining charge of the built-in battery.

[0087] In addition, the operation indicator 150 located on the upper surface of the main body 200 has a function of notifying the fluid delivery status of the infusion pump 100, and flashes a predetermined color (e.g., green) while fluid delivery is in progress, but if fluid delivery stops due to an abnormality, it lights up or flashes a predetermined color different from the color during fluid delivery (e.g., red).

[0088] Next, the configuration of the main body 200 of the infusion pump 100 and the rear side of the door 110 will be described. The infusion tube 160 shown in Fig. 7 is installed in a linear hollow section defined between the door 110 and the main body 200. The position of the infusion tube 160 is fixed within the hollow section.

[0089] As shown in FIG. 8, the main body 200 includes an air bubble detection sensor 21 as the air bubble detection device 1, a liquid delivery section 22, an occlusion sensor section 23, a tube clamp holding section 24, a release lever section 25, a tube regulating section 26, and a clamping section 27.

[0090] The air bubble detection sensor 21 serving as the air bubble detection device 1 detects the presence or absence of air bubbles in the infusion tube 160 (see FIG. 7) serving as the tubular body 50 when the door portion 110 is in a closed state. As described above, the air bubble detection sensor 21 of this embodiment can detect the presence or absence of air bubbles in the infusion tube 160 (see FIG. 7) serving as the tubular body 50 by using a plurality of electrodes 2 (see FIGS. 1, 2, etc.).

[0091] In the infusion pump 100, the above-mentioned control unit 4 (see FIG. 1, etc.) of the air bubble detection device 1 may be configured to be doubled up as a control unit that controls the operation of the entire infusion pump 100. In addition, the above-mentioned notification unit 5 (see FIG. 1, etc.) of the air bubble detection device 1 may be doubled up as the air bubble detection display unit 125 of the alarm display unit 123 of the display unit 120 in the infusion pump 100, the operation indicator 150, etc. In addition, the above-mentioned information input unit 6 (see FIG. 3) of the air bubble detection device 1 may be doubled up as the operation unit 130 in the infusion pump 100.

[0092] The liquid delivery unit 22 is capable of delivering liquid in an infusion tube 160 serving as a tubular body 50. The liquid delivery unit 22 of this embodiment includes a plurality of fingers 15a-15h and a drive unit for driving the fingers 15a-15h. The drive unit includes a motor for generating a desired rotational torque, a camshaft that is rotationally driven by the motor via a transmission mechanism, a bearing for supporting the camshaft, and a plurality of eccentric drive cams that are fixed to the camshaft at individual eccentric angles. The fingers 15a-15h are pressed by the respective eccentric drive cams, and can reciprocate in a direction opposite to a receiving unit 204 described later.

[0093] The multiple fingers 15a to 15h are arranged from the upstream side of the flow path of the infusion tube 160 to the downstream side of the flow path (in the liquid sending direction). The multiple fingers 15a to 15h are driven by the above-mentioned drive unit to sequentially press and close the infusion tube 160. This allows the infusion tube 160 to perform peristaltic motion.

[0094] The occlusion sensor unit 23 is composed of a permanent magnet and a pickup for analog detection of the amount of movement of the permanent magnet. The occlusion sensor unit 23 detects the occlusion state of the infusion tube 160 (see FIG. 7) by detecting the amount of movement of the permanent magnet that has moved in response to a change in internal pressure associated with the occlusion state of the infusion tube 160 (see FIG. 7).

[0095] The tube clamp holding portion 24 holds a clamp attached to the infusion tube 160 (see FIG. 7) and, when the door portion 110 is in the open state, applies a pressing force to the clamp to temporarily press and close the infusion tube 160 (see FIG. 7).

[0096] The release lever portion 25 is operated by an operator such as a medical professional to release the pressure applied to the clamp by the tube clamp holding portion 24 (that is, release the clamp from compressing the infusion tube 160 (see FIG. 7)).

[0097] When the infusion tube 160 (see FIG. 7) is attached to the main body portion 200, the tube defining portion 26 defines the position of the infusion tube 160 (see FIG. 7) in a direction perpendicular to the central axis direction.

[0098] As shown in FIGS. 7 and 8, the main body 200 may further include a handle 28 for a user to grasp when carrying the infusion pump 100.

[0099] 8, the door section 110 includes a door housing 110a. This door housing 110a is rotatably attached to a main body housing 200a of the main body section 200 via a hinge section 202. In this manner, the door section 110 of the present embodiment is configured to be freely opened and closed with respect to the main body section 200.

[0100] A door seal rubber 203 made of an elastomer is disposed on the rear side of the door portion 110 to prevent the liquid medicine from entering the inside of the main body portion 200 when the door portion 110 is in the closed state.

[0101] In addition, a position maintaining portion 108 is disposed on the rear side of the door portion 110. When the door portion 110 is closed relative to the main body portion 200, the position maintaining portion 108 comes into contact with the infusion tube 160 (see FIG. 7) and determines the position of the infusion tube 160 within the hollow portion.

[0102] A receiving portion 204 is disposed on the rear side of the door portion 110. The receiving portion 204 sandwiches the infusion tube 160 between itself and the liquid delivery portion 22.

[0103] Furthermore, a closure presser plate 205 is disposed on the rear side of the door portion 110. When the door portion 110 is in the closed state, the closure presser plate 205 clamps the infusion tube 160 (see FIG. 7) between itself and the closure sensor portion 23.

[0104] 8, the air bubble detection sensor 21 as the air bubble detection device 1 is disposed at the mounting part 200a1 of the main body 200 where the infusion tube 160 (see FIG. 7) as the tubular body 50 is disposed. Specifically, the air bubble detection sensor 21 is provided so that a plurality of electrodes 2 are exposed to the mounting part 200a1 of the main body 200. In FIG. 8, an upstream electrode 2c, a central electrode 2d, and a downstream electrode 2e (see FIGS. 4A and 4B) are illustrated as the plurality of electrodes 2.

[0105] Therefore, according to the air bubble detection sensor 21 serving as the air bubble detection device 1, the presence or absence of air bubbles in the infusion tube 160 serving as the tubular body 50 attached to the infusion pump 100 can be detected with a simple configuration by utilizing the presence or absence of electrical current flow between the electrodes 2.

[0106] 8, the infusion pump 100 is disposed downstream of the flow path in the upstream / downstream direction A with respect to a plurality of electrodes 2 (the upstream electrode 2c, the central electrode 2d, and the downstream electrode 2e in FIG. 8) of the air bubble detection sensor 21 as the air bubble detection device 1. The infusion pump 100 of this embodiment includes a clamping portion 27 that is capable of clamping the infusion tube 160 as the tubular body 50 at a position between the plurality of electrodes 2 of the air bubble detection sensor 21 as the air bubble detection device 1 in the upstream / downstream direction A and abuts against the outer surface of the infusion tube 160 as the tubular body 50. More specifically, the clamping portion 27 of this embodiment is configured to be capable of clamping the infusion tube 160 at a position between the central electrode 2d and the downstream electrode 2e.

[0107] By providing such a clamping portion 27, even if there is a foreign object Z (see Figs. 6B and 6C) such as a medicinal liquid that runs along the outer surface of the infusion tube 160 as the tubular body 50 and infiltrates into the infusion pump 100, the clamping portion 27 makes it difficult for the foreign object Z to reach the position of the downstream electrode 2e. In other words, it is possible to prevent at least the downstream detection section N2 between the central electrode 2d and the downstream electrode 2e from becoming in a state in which air bubbles cannot be detected due to the presence of the foreign object Z (see Figs. 6B and 6C). Therefore, even if the foreign object Z adheres to the outer surface of the infusion tube 160 as the tubular body 50, the air bubbles can be more reliably detected by the two electrodes 2 (the central electrode 2d and the downstream electrode 2e in this embodiment) arranged to sandwich the clamping portion 27 in the upstream / downstream direction A. In addition, the two electrodes 2 (in this embodiment, the central electrode 2d and the downstream electrode 2e) arranged on either side of the clamping portion 27 in the upstream / downstream direction A can more reliably estimate the presence of a foreign object Z in the upstream detection section N1 between the upstream electrode 2c and the central electrode 2d (see Figure 6B).

[0108] The clamping portion 27 may be formed, for example, integrally with the main body housing 200a of the main body 200. That is, the clamping portion 27 may be formed of an insulating material such as resin or rubber.

[0109] In addition, in this embodiment, an upstream electrode 2c, a central electrode 2d, and a downstream electrode 2e are used as the multiple electrodes 2, and the clamping portion 27 clamps the infusion tube 160 as the tubular body 50 at a position between the central electrode 2d and the downstream electrode 2e, but this configuration is not limited to this.

[0110] The plurality of electrodes 2 may be two electrodes 2 arranged at a distance in the upstream / downstream direction A. That is, the air bubble detection sensor 21 as the air bubble detection device 1 may be configured to have only two electrodes, an upstream electrode 2a and a downstream electrode 2b (see FIG. 1, etc.). In this case, the clamping portion 27 may be configured to clamp the infusion tube 160 as the tubular body 50 in the detection section N (see FIG. 1, etc.) between the upstream electrode 2a and the downstream electrode 2b. This can prevent the detection section N between the upstream electrode 2a and the downstream electrode 2b from becoming unable to detect air bubbles due to the presence of a foreign object Z (see FIGS. 6B and 6C). Therefore, even if the foreign object Z adheres to the outer surface of the infusion tube 160 as the tubular body 50, the air bubbles can be more reliably detected by the upstream electrode 2a and the downstream electrode 2b arranged to sandwich the clamping portion 27 in the upstream / downstream direction A.

[0111] Furthermore, the plurality of electrodes 2 may be four or more electrodes 2 spaced apart in the upstream / downstream direction A. The clamping unit 27 may be configured to clamp the infusion tube 160 as the tubular body 50 between any two electrodes 2 adjacent to each other in the upstream / downstream direction A. In other words, the clamping unit 27 is not limited to a configuration in which the clamping unit 27 clamps the infusion tube 160 in the downstream detection section N2, which is the most downstream detection section N in the flow path, as in the present embodiment, but may be configured to clamp the infusion tube 160 in any detection section N upstream of the most downstream detection section N in the flow path, such as the upstream detection section N1.

[0112] Furthermore, an upstream occlusion sensor unit having a configuration similar to that of the above-mentioned occlusion sensor unit 23 may be provided between any two electrodes 2 (e.g., the central electrode 2d and the downstream electrode 2e) adjacent in the upstream / downstream direction A, so that foreign matter Z such as a medicinal liquid that has infiltrated from upstream along the infusion tube 160 is less likely to infiltrate further downstream beyond the upstream occlusion sensor unit. In this way, it is possible to prevent the detection section N between the two electrodes 2 (e.g., the central electrode 2d and the downstream electrode 2e) from becoming unable to detect bubbles due to the presence of the foreign matter Z (see Figs. 6B and 6C).

[0113] The air bubble detection device and liquid delivery pump according to the present disclosure are not limited to the specific configurations shown in the above-described embodiments and modified examples, and various changes, modifications, and combinations are possible without departing from the scope of the claims. [Industrial Applicability]

[0114] The present disclosure relates to an air bubble detection device and a liquid delivery pump. [Explanation of symbols]

[0115] 1: Air bubble detector 1a: Sensor section 2: Electrode 2a: Upstream electrode 2b: Downstream electrode 2c: Upstream electrode 2d: Central electrode 2e: Downstream electrode 2f: 1st electrode 2g: 2nd electrode 2h: 3rd electrode 2i: 4th electrode 2j: 5th electrode 3: Voltage application section 3a: AC power supply 4: Control unit 5: Notification Department 6: Information input section 7: Time measurement section 10a, 10b: Conductor 15a~15h: Finger 21: Air bubble detection sensor (an example of an air bubble detection device) 22: Liquid delivery section 23: Occlusion sensor unit 24: Tube clamp holder 25: Release lever part 26: Tube regulation section 27: Holding part 28: Handle 50: Body 50a: Flow path 100: Infusion pump (an example of a fluid delivery pump) 108: Position holding part 110: Door section 110a: Door housing 120: Display section 121:Flow rate display section 122: Scheduled amount and accumulated amount display section 123: Alarm display section 124: Occlusion pressure setting display unit 125: Air bubble detection display unit 126: Battery voltage drop indicator 127: Occlusion abnormality display section 128: Door open status indicator 129:Completion display area 130:Operation unit 131: Up / down switch 132: Fast forward switch 133: Stop switch 134: Start switch 135: Power switch 136: Power lamp 137: Battery lamp 140: Door lock lever 150: Operation indicator 160: Infusion tube (an example of a tube) 161: Infusion bag 162: Clamping member 163: Indwelling catheter 200: Main body 200a: Main body housing 200a1: Mounting part 202: Hinge part 203: Door seal rubber 204: Receiving part 205: Closure plate A: Upstream / downstream D1: Channel diameter L1: Distance traveled by the bubble during the non-energized period L2: Length of the detection section L3: Length of the bubble L4: Electrode contact length L5: Bubble length threshold N: Detection section N1: Upstream detection section N2: Downstream detection section N3: First detection section N4: Second detection section N5: Third detection section N6: 4th detection section T1: De-energized time X:Liquid Y: Air bubbles Z: Foreign object

Claims

1. a plurality of electrodes that can be arranged on an outer surface of a tube that defines a flow path through which a liquid can flow, and that can be arranged at different positions in the upstream and downstream directions of the flow path; a voltage application unit capable of applying an AC voltage between any two of the plurality of electrodes adjacent to each other in the upstream / downstream direction; a control unit that detects the presence or absence of bubbles in a detection section between the two electrodes in the upstream and downstream directions of the pipe based on the presence or absence of electrical current between the two electrodes.

2. 2. The bubble detection device according to claim 1, wherein when there is no current flow between at least one set of two electrodes adjacent to each other in the upstream / downstream direction among the plurality of electrodes, the control unit estimates a bubble volume based on a time of no current flow in the detection section between the at least one set of two electrodes.

3. the plurality of electrodes includes three or more electrodes forming two or more detection zones therebetween; The bubble detection device according to claim 1 , wherein the control unit estimates a bubble volume based on combined information regarding the presence or absence of current flow in each of the two or more detection sections.

4. The air bubble detection device according to claim 2 , further comprising a notification unit that notifies an outside source when the air bubble volume estimated by the control unit is equal to or greater than a predetermined threshold value.

5. the plurality of electrodes includes three or more electrodes forming two or more detection zones therebetween; The bubble detection device according to claim 1 , wherein the control unit estimates the presence or absence of a foreign object adhering to the outer surface of the tube based on time history information on the presence or absence of current flow in each of the two or more detection sections.

6. A liquid delivery pump comprising the air bubble detection device according to claim 1 or 2.

7. a liquid delivery section that is disposed on a downstream side of the flow path in the upstream / downstream direction with respect to the plurality of electrodes of the bubble detection device and is capable of delivering the liquid in the tubular body; 7. The liquid feed pump according to claim 6, further comprising: a clamping portion configured to abut against an outer surface of the tubular body at a position between the plurality of electrodes of the bubble detection device in the upstream / downstream direction and to clamp the tubular body.

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