JPWO2020070953A1 - Intravenous monitoring sensor - Google Patents

Abstract

The drip monitoring sensor according to the present disclosure is a drip monitoring sensor that can be attached to a drip tube and monitors a liquid falling inside the drip tube, and is arranged outside the drip tube in the radial direction and said to drip. A light emitting portion capable of simultaneously irradiating the inside of the drip cylinder from different positions in the circumferential direction of the cylinder and a light emitting portion facing the light emitting portion with the drip cylinder sandwiched between them and capable of receiving the irradiation light. It is provided with a light receiving unit and a light guide unit that is arranged between the drip tube and the light receiving unit and internally partitions a light guide path that limits the irradiation light received by the light receiving unit.

Description

The present disclosure relates to a drip monitoring sensor.

An infusion device equipped with an infusion tube is used to administer a liquid such as a nutritional supplement or a drug solution to a living body such as a patient. The infusion device includes a drip tube, an infusion tube, various other medical devices, and the like, and a route (infusion line) for transporting the liquid is formed by these. The infusion tube is equipped with a clamp, an infusion pump, or the like for adjusting the flow rate of the liquid flowing through the infusion line.

A drip monitoring sensor for monitoring a liquid falling inside a drip tube provided in the above-mentioned infusion device or the like is known. As such a drip monitoring sensor, Patent Document 1 discloses a configuration using a photointerruptor having a light emitting element that irradiates light and a light receiving element that receives light.

Japanese Patent No. 6315149

In the infusion device, for example, the flow rate of the liquid flowing through the infusion line may become excessive due to forgetting to close the clamp, malfunction of the infusion pump, or the like. When the flow rate becomes excessive, the liquid does not drop intermittently (hereinafter referred to as "droplet state") but continuously drops in a columnar state (hereinafter referred to as "liquid column state"). .) May be. However, Patent Document 1 does not describe detecting the state of a liquid column of a liquid falling inside the drip tube.

An object of the present disclosure is to provide a drip monitoring sensor having a configuration that makes it easy to detect both a liquid droplet state and a liquid column state of a liquid falling inside a drip tube.

The drip monitoring sensor as the first aspect of the present disclosure is a drip monitoring sensor that can be attached to the drip tube and monitors the liquid falling inside the drip tube, and is located outside the drip tube in the radial direction. A light emitting portion that is arranged and capable of simultaneously irradiating the inside of the drip cylinder with irradiation light from different positions in the circumferential direction of the drip cylinder and a light emitting portion that is arranged so as to face the light emitting portion with the drip cylinder in between and the irradiation. It includes a light receiving unit capable of receiving light, and a light guide unit that is arranged between the drip tube and the light receiving unit and internally partitions a light guide path that limits the irradiation light received by the light receiving unit.

The drip monitoring sensor as one embodiment of the present disclosure includes a housing for holding the light emitting portion and the light receiving portion, and the housing partitions a storage space capable of accommodating the drip cylinder. The shortest distance from the light emitting portion to the accommodation space in the radial direction of the drip tube is the shortest distance from the light receiving portion to the accommodation space in the radial direction of the drip tube. Shorter than.

As one embodiment of the present disclosure, an inlet opening of the light guide path through which the irradiation light can enter the light guide path is defined on an end surface of the light guide portion arranged so as to face the drip tube. The shortest distance from the entrance opening of the light guide path to the light receiving portion is longer than the maximum light entry width of the entrance opening of the light guide path.

In the drip monitoring sensor as one embodiment of the present disclosure, when the light guide path is the first light guide path and the light guide portion is the first light guide portion, the drip tube and the light emitting portion are between the drip cylinder and the light emitting portion. It is provided with a second light guide portion that is arranged and internally partitions a second light guide path that limits the irradiation light emitted from the light emitting unit to the inside of the drip tube.

In one embodiment of the present disclosure, the length of the first light guide path is longer than the length of the second light guide path.

As one embodiment of the present disclosure, the light emitting unit includes a plurality of light emitting elements arranged in the same horizontal plane in which the central rays of the emitted light are parallel to each other.

As one embodiment of the present disclosure, the light emitting unit includes a light emitting element and an optical element capable of converting light emitted from the light emitting element into parallel light.

As one embodiment of the present disclosure, the light receiving unit includes a plurality of light receiving elements arranged in the same horizontal plane in which the central rays of the received light are parallel to each other.

As one embodiment of the present disclosure, the light receiving unit includes a light receiving element and an optical element capable of condensing light received by the light receiving element.

The drip monitoring sensor as one embodiment of the present disclosure includes a liquid column detection unit that detects a liquid column state of the liquid based on a change in the amount of received irradiation light received by the light receiving unit.

As one embodiment of the present disclosure, the liquid column detection unit is used when the amount of received irradiation light received by the light receiving unit decreases by a predetermined amount or more over a predetermined time with respect to a predetermined threshold value. , The state of the liquid column of the liquid is detected.

As one embodiment of the present disclosure, the light receiving unit includes an upper light receiving unit and a lower light receiving unit installed at different positions in the vertical direction.

As one embodiment of the present disclosure, the liquid column detecting unit is a liquid column detecting unit that detects a liquid column state of the liquid based on a change in the amount of received irradiation light received by the upper light receiving unit. A lower liquid column detecting unit that detects the liquid column state of the liquid based on a change in the amount of received irradiation light received by the lower light receiving unit is provided, and the upper liquid column detecting unit determines the liquid column state. It is provided with a liquid column determining unit that detects and determines that the liquid is falling in the liquid column state when the lower liquid column detecting unit detects the liquid column state.

As one embodiment of the present disclosure, the light receiving unit includes an external light receiving unit capable of receiving external light, and the liquid column determination unit changes the amount of external light received by the external light receiving unit. Based on this, it is determined whether or not the liquid is falling in a liquid column state.

As one embodiment of the present disclosure, a droplet detection unit that detects a droplet state of the liquid based on a change in the amount of received irradiation light received by the light receiving unit is provided.

As one embodiment of the present disclosure, the light receiving unit includes an upper light receiving unit and a lower light receiving unit installed at different positions in the vertical direction, and the droplet detecting unit is the irradiation received by the upper light receiving unit. An upper droplet detection unit that detects the liquid droplet state based on a change in the amount of light received, and a liquid droplet of the liquid based on a change in the amount of irradiation light received by the lower light receiving unit. The lower droplet detection unit for detecting the state is provided, and the upper droplet detection unit detects the droplet state, and the upper droplet detection unit detects the droplet state within a predetermined time. When the lower droplet detection unit detects the droplet state, it includes a droplet determination unit that determines that the liquid is falling in the droplet state.

According to the present disclosure, it is possible to provide a drip monitoring sensor having a configuration that makes it easy to detect both a liquid droplet state and a liquid column state of a liquid falling inside a drip tube.

It is a figure which shows an example of the infusion apparatus in the state which the drip monitoring sensor of 1st Embodiment of this disclosure is attached to a drip tube. It is a figure which shows the part of FIG. 1 enlarged, and is the front view of the drip monitoring sensor in the state which is attached to the drip tube. It is a block diagram which shows the structure of the drip monitoring sensor shown in FIG. It is a figure which shows the positional relationship when the drip tube and the main part of the drip monitoring sensor are seen from above with the drip monitoring sensor shown in FIG. 1 attached to the drip tube. It is a figure which shows the main part of the drip monitoring sensor as a comparative example. It is a figure which shows the change of the total light-receiving amount per unit time which the light-receiving part of the drip monitoring sensor as a comparative example shown in FIG. 5 receives. FIG. 6A shows a change in the total amount of light received per unit time of the light receiving portion caused by droplets of opaque liquid. FIG. 6B shows a change in the total amount of light received per unit time of the light receiving portion caused by droplets of the transparent liquid. It is a figure which shows the change of the total light-receiving amount per unit time which the light-receiving part of the drip monitoring sensor as a comparative example shown in FIG. 5 receives. It is a figure which shows an example of the received light signal when the falling liquid is a transparent liquid and is a droplet state, and the period of the moving interval integration of an amplitude. 9 (a) and 9 (b) are diagrams showing an example of a peak waveform generated in a received signal by a falling liquid in a droplet state. FIG. 9A is a light receiving signal detected when the falling liquid is a droplet of an opaque liquid. FIG. 9B is a light receiving signal detected when the falling liquid is a droplet of a transparent liquid. 10 (a) and 10 (b) are diagrams showing waveforms obtained by converting the peak waveforms shown in FIGS. 9 (a) and 9 (b) into moving section integral waveforms of amplitude. It is a figure explaining the liquid column state detection process by the liquid column detection part shown in FIG. It is a figure which shows the main part of the drip monitoring sensor as the 2nd Embodiment of this disclosure. It is a figure which shows the main part of the drip monitoring sensor as the 3rd Embodiment of this disclosure. It is a front view of the drip monitoring sensor as the 4th embodiment of the present disclosure in the state of being attached to the drip tube 110. It is a block diagram which shows the structure of the drip monitoring sensor shown in FIG. FIG. 16A shows the upper light receiving part and the upper light receiving part when the liquid does not actually fall in the liquid column state and the lower light receiving part detects a droplet that adheres to the inner surface of the drip tube and does not fall. It is a figure which shows the change of the light receiving amount of the lower light receiving part. FIG. 16B is a diagram showing changes in the amount of light received by the upper light receiving portion and the lower light receiving portion when the liquid is actually dropped in a liquid column state. It is a figure which shows the outline of the experimental system of the confirmation experiment. FIG. 18A is a diagram showing the emission characteristics of the light emitting element used in the confirmation experiment shown in FIG. FIG. 18B is a diagram showing the incident characteristics of the light receiving element used in the confirmation experiment shown in FIG. FIG. 19A is a diagram showing a change in the amount of light received by the light receiving portion due to droplets of the opaque liquid. FIG. 19B is a diagram showing a change in the amount of light received by the light receiving portion due to droplets of the transparent liquid. It is a figure which shows the change of the light receiving amount of the light receiving part when the opaque liquid changes from the droplet state to the liquid column state. It is a figure which shows the change of the light receiving amount of the light receiving part when the transparent liquid changes from the droplet state to the liquid column state. FIG. 22A is a diagram showing a change in the amount of light received by the light receiving portion due to droplets of the transparent liquid. FIG. 22B is a diagram showing a change in the amount of light received by the light receiving portion when the transparent liquid changes from a droplet state to a liquid column state.

Hereinafter, embodiments of the drip monitoring sensor according to the present disclosure will be described with reference to the drawings. The same reference numerals are given to common members and parts in each figure. In the present specification, the vertical direction means the vertical direction. The drip tube 110, which will be described later, is arranged so that the axial direction is along the vertical direction when used in a living body. The upper part means the direction in which the dropping part 111 is located (that is, the upper part in FIG. 2) when viewed from the discharging part 112, and the lower part means the opposite direction.

(First Embodiment)
FIG. 1 is a diagram showing an example of an infusion device 100 in a state where the drip monitoring sensor 1 of the first embodiment is attached to the drip tube 110. FIG. 2 is an enlarged view of a part of FIG. 1, and is a front view of the drip monitoring sensor 1 in a state of being mounted on the drip tube 110. FIG. 3 is a block diagram showing the configuration of the drip monitoring sensor 1. The arrow shown in FIG. 3 indicates the direction in which the electric signal flows. FIG. 4 is a diagram showing a positional relationship when the drip tube 110 and the main part of the drip monitoring sensor 1 are viewed from above with the drip monitoring sensor 1 mounted on the drip tube 110.

The infusion device 100 shown in FIG. 1 is used to administer a liquid such as a nutritional supplement or a drug solution to a living body such as a patient. The infusion device 100 forms an infusion line for transporting the liquid to the living body. Specifically, the infusion device 100 includes an infusion container 101 such as an infusion bag containing a liquid, an infusion tube 110 capable of visually recognizing the flow rate of the liquid supplied from the infusion container 101, an indwelling needle indwelled in a living body, and the like. A connector 102 that can be connected to the infusion tube 103 and a plurality of infusion tubes 103 that connect each of these members are provided. The infusion line is formed by an infusion container 101, an infusion tube 110, a connector 102, and an infusion tube 103. In the example shown in FIG. 1, the infusion device 100 further includes a clamp 104 and an infusion pump 105 mounted on the infusion tube 103 for adjusting the flow rate of the liquid flowing through the infusion line.

As shown in FIG. 2, the drip tube 110 has a dropping portion 111 that introduces the liquid transported from the upstream of the infusion line into the internal dropping chamber 113, and discharges the liquid in the dropping chamber 113 to the downstream of the infusion line. A discharge portion 112 and a peripheral wall portion 114 for partitioning the peripheral surface of the dropping chamber 113 are provided. The peripheral wall portion 114 includes at least a part of a light transmitting portion formed of a light transmitting material. Specifically, the light transmitting portion of the peripheral wall portion 114 is provided at least at a position above the liquid level of the stored liquid 117, which will be described later.

The liquid transported to the drip tube 110 falls from the drip portion 111 as a falling liquid 116, and is stored in the drip chamber 113 as a stored liquid 117. The discharge unit 112 discharges a part of the stored liquid 117. Therefore, the stored liquid 117 is kept in an appropriate amount.

As shown in FIGS. 1 and 2, the drip monitoring sensor 1 can be attached to the drip tube 110. As shown in FIGS. 1 and 2, the drip monitoring sensor 1 is used in a state of being mounted around the drip tube 110. Specifically, the drip monitoring sensor 1 can monitor the liquid falling inside the drip tube 110 while it is attached to the drip tube 110. More specifically, the drip monitoring sensor 1 of the present embodiment is used to monitor the falling liquid 116 falling in the drip chamber 113 inside the drip cylinder 110. As shown in FIG. 2, the drip monitoring sensor 1 of the present embodiment sandwiches the peripheral wall portion 114 at the position of the light transmitting portion of the peripheral wall portion 114 of the drip cylinder 110 above the liquid level of the stored liquid 117. It is attached in this way.

As shown in FIG. 2, the drip monitoring sensor 1 of the present embodiment includes a light emitting unit 10, a light receiving unit 20, a light guide unit 30, a liquid column detection unit 50, a droplet detection unit 60, and an amplification unit 70. The notification unit 80 and the housing 2 are provided.

As shown in FIGS. 2 and 4, the light emitting unit 10 is arranged outside the drip tube 110 in the radial direction A. Further, as shown in FIG. 4, the light emitting unit 10 can simultaneously irradiate the inside of the drip tube 110 with the irradiation light L1 from different positions in the circumferential direction B of the drip tube 110. More specifically, the light emitting unit 10 can irradiate the irradiation light L1 toward the falling liquid 116 that falls in the drip chamber 113 of the drip tube 110 through the light transmitting portion of the peripheral wall portion 114. As shown in FIG. 4, the light emitting unit 10 of the present embodiment has a width equal to or larger than the outer diameter of the drip tube 110. The light emitting unit 10 of the present embodiment can irradiate the entire inside of the drip tube 110 with the irradiation light L1 in the horizontal plane H (see FIG. 2) which is the same horizontal plane. The light emitting unit 10 includes, for example, a light emitting element 11 that emits light such as one or more LEDs (Light Emitting Diodes) or a laser diode. In the present embodiment, as shown in FIG. 4, seven light emitting elements 11a to 11g are arranged outside the peripheral wall portion 114 of the drip tube 110 in the horizontal plane H (see FIG. 2) which is the same horizontal plane. , The number of light emitting elements arranged is not particularly limited. The central rays of light emitted from the plurality of light emitting elements 11a to 11g of the present embodiment are parallel to each other. The central ray of light emitted from a light emitting element means the strongest light ray emitted from the light emitting element. In FIG. 4, for convenience, only the central ray of the irradiation light L1 emitted from the light emitting elements 11a to 11c and 11e to 11g is shown.

As shown in FIGS. 2 and 4, the light receiving unit 20 is arranged so as to face the light emitting unit 10 with the drip tube 110 interposed therebetween. "The light receiving portion is arranged so as to face the light emitting portion with the drip cylinder in between" means a positional relationship in which at least one linear optical path connecting the light emitting portion and the light receiving portion passes through the inside of the drip cylinder. .. Further, the light receiving unit 20 can receive the irradiation light L1 emitted from the light emitting unit 10 to the drip tube 110. Specifically, the irradiation light L1 that can be received by the light receiving unit 20 includes transmitted light transmitted through the falling liquid 116 including the refracted light refracted inside the falling liquid 116, and reflected light reflected by the falling liquid 116. Direct light, which was not applied to the falling liquid 116, is included. The light receiving unit 20 includes, for example, a light receiving element 21 such as one or more phototransistors or photodiodes. The light receiving unit 20 outputs a light receiving signal based on the received light receiving amount of the received irradiation light L1 to the liquid column detecting unit 50 and the droplet detecting unit 60 via the amplifying unit 70. As shown in FIG. 2, in the drip monitoring sensor 1 of the present embodiment, the light emitting unit 10 and the light receiving unit 20 are located in a horizontal plane H which is the same plane. In the present embodiment, as shown in FIG. 4, seven light receiving elements 21a to 21g are arranged outside the peripheral wall portion 114 of the drip tube 110 in the horizontal plane H (see FIG. 2) which is the same plane. , The number of light receiving elements arranged is not particularly limited. The central rays of light received by the plurality of light receiving elements 21a to 21g of the present embodiment are parallel to each other. The central ray of light received by the light receiving element means a light ray that is most easily received by the light receiving element, in other words, has the highest light receiving efficiency.

As shown in FIG. 4, the light emitting element 11a of the light emitting unit 10 and the light receiving element 21a of the light receiving unit 20 are arranged so as to face each other. When the drip tube 110 does not intervene between the light emitting element 11a of the light emitting unit 10 and the light receiving element 21a of the light receiving unit 20, the central ray of light emitted from the light emitting element 11a of the light emitting unit 10 is the light receiving element of the light receiving unit 20. 21a becomes a central ray that receives light. When the drip tube 110 is interposed between the light emitting element 11a of the light emitting unit 10 and the light receiving element 21a of the light receiving unit 20 (see FIG. 4), the central ray of light emitted from the light emitting element 11a of the light emitting unit 10 is drip. It may be refracted and / or reflected by the peripheral wall portion 114 of the cylinder 110. In such a case, the central ray of light emitted from the light emitting element 11a of the light emitting unit 10 does not become the central ray received by the light receiving element 21a of the light receiving unit 20. However, in FIG. 4, for convenience of explanation, refraction and / or reflection by the peripheral wall portion 114 of the drip tube 110 is not taken into consideration, and the central ray of light emitted from the light emitting element 11a of the light emitting unit 10 is transmitted to the light receiving unit 20. It is drawn assuming that it coincides with the central light beam received by the light receiving element 21a of.

Each of the light emitting elements 11b to 11g of the light emitting unit 10 has the same relationship as the light emitting element 11a of the light emitting unit 10 and the light receiving element 21a of the light receiving unit 20 with each of the light receiving elements 21b to 21g of the light receiving unit 20.

As shown in FIGS. 2 and 4, the light guide unit 30 is arranged between the drip tube 110 and the light receiving unit 20. Further, as shown in FIG. 4, the light guide unit 30 internally partitions a light guide path 31 that limits the irradiation light L1 received by the light receiving unit 20. The light guide unit 30 is configured so as not to transmit the irradiated light and not to totally reflect the irradiated light. For example, a microconcavo-convex structure that diffusely reflects the irradiated light may be formed on the outer surface and the inner surface of the light guide unit 30. Further, the light guide unit 30 may be configured to be able to absorb a part or all of the irradiated light, for example, it may be formed of a black opaque resin or covered with a black paint. The light guide unit 30 of the present embodiment is composed of a tubular body that internally partitions the light guide path 31. The light guide unit 30 of the present embodiment partitions the inlet opening 31a of the light guide path 31 through which the irradiation light L1 can enter the light guide path 31 on the end surface on one end side which is arranged so as to face the drip tube 110. .. Further, the light guide unit 30 of the present embodiment has an outlet opening 31b of the light guide path 31 capable of emitting light from the light guide path 31 toward the light receiving unit 20 on the other end surface arranged facing the light receiving unit 20. It is partitioned. The light guide unit 30 of the present embodiment is composed of seven tubular bodies corresponding to each of the light receiving elements 21a to 21g, but may have a configuration in which seven light guide paths are formed in one member. ..

As described above, the light emitting unit 10 can simultaneously irradiate the inside of the drip tube 110 with the irradiation light L1 from different positions in the circumferential direction B of the drip tube 110. Although the details will be described later, by providing the light guide unit 30, the light receiving unit 20 detects the “shadow” component of the liquid falling inside the drip tube 110 even in the configuration including the light emitting unit 10 described above. It becomes easier to do. Therefore, regardless of the transparency of the liquid, the state of the liquid droplets and the state of the liquid column falling inside the drip tube can be easily detected.

The liquid column detection unit 50 can detect the state of the liquid column of the liquid based on the change in the amount of light received by the irradiation light L1 received by the light receiving unit 20. More specifically, the liquid column detection unit 50 of the present embodiment can detect the liquid column state of the falling liquid 116 based on the light receiving signal from the light receiving unit 20. The liquid column detection unit 50 can detect the state of the liquid column based on the change in the total amount of light received per unit time received by the light receiving unit 20. That is, the liquid column detection unit 50 of the present embodiment can detect the liquid column state based on the change in the total amount of light received per unit time received by the seven light receiving elements 21a to 21g. In the liquid column detection unit 50 of the present embodiment, when the light receiving amount of the irradiation light L1 received by the light receiving unit 20 decreases by a predetermined amount or more over a predetermined time with respect to a predetermined threshold value, the falling liquid 116 Detect the liquid column state. The liquid column detection unit 50 performs a predetermined function by reading, for example, a storage device that stores various information and programs, and a predetermined information and program among various information and programs stored in the storage device. It is composed of a processor to be realized. Details of the method by which the liquid column detecting unit 50 detects the liquid column state of the falling liquid 116 will be described later (see FIG. 11). When the liquid column detection unit 50 detects the liquid column state, the liquid column detection unit 50 outputs the detection result to the notification unit 80.

The droplet detection unit 60 can detect the liquid droplet state based on the change in the amount of light received by the irradiation light L1 received by the light receiving unit 20. More specifically, the droplet detection unit 60 of the present embodiment can detect the droplet state of the falling liquid 116 based on the light receiving signal from the light receiving unit 20. The droplet detection unit 60 can detect the droplet state based on the change in the total amount of light received per unit time received by the light receiving unit 20. That is, the droplet detection unit 60 of the present embodiment can detect the droplet state based on the change in the total amount of light received per unit time received by the seven light receiving elements 21a to 21g. The droplet detection unit 60 of the present embodiment detects the droplet state of the falling liquid 116 when the light receiving amount of the irradiation light L1 received by the light receiving unit 20 changes by a predetermined amount or more in a predetermined time. The droplet detection unit 60 performs a predetermined function by reading, for example, a storage device that stores various information and programs, and a predetermined information and program among various information and programs stored in the storage device. It is composed of a processor to be realized. The storage device, processor, etc. constituting the droplet detection unit 60 may be a member common to the storage device, processor, etc., which constitutes the liquid column detection unit 50, or may be a separate member. Details of the method by which the droplet detection unit 60 detects the droplet state of the falling liquid 116 will be described later (see FIGS. 8 to 10 and the like). When the droplet detection unit 60 detects the droplet state, the droplet detection unit 60 outputs the detection result to the notification unit 80.

The amplifier unit 70 is composed of, for example, an amplifier circuit or the like, amplifies the light-receiving signal from the light-receiving unit 20, and outputs the signal to the liquid column detection unit 50 and the droplet detection unit 60.

The notification unit 80 notifies the detection result from the liquid column detection unit 50 and the detection result from the droplet detection unit 60 to the outside. Specifically, the notification unit 80 may be composed of, for example, a speaker, and may notify the detection result by sound. The notification unit 80 may be composed of, for example, a light emitting element or a display device, and may notify the detection result by light. The notification unit 80 may be composed of, for example, a wired or wireless communication device, and may notify by transmitting the detection result to an external device. The external device may be, for example, an infusion pump 105 (see FIG. 1), in which case the infusion pump 105 may adjust the flow rate of liquid flowing through the infusion line based on the detection result.

As shown in FIG. 2, the housing 2 holds a light emitting unit 10 and a light receiving unit 20. More specifically, the housing 2 of the present embodiment includes not only the light emitting unit 10 and the light receiving unit 20, but also the light guide unit 30, the liquid column detection unit 50, the droplet detection unit 60, the amplification unit 70, and the notification unit 80 described above. Also holds about. The housing 2 constitutes an exterior member of the drip monitoring sensor 1. Further, the housing 2 partitions a storage space 2a capable of accommodating the drip tube 110. The drip monitoring sensor 1 of the present embodiment is attached to the drip tube 110 so that the drip tube 110 is housed in the accommodation space 2a of the housing 2.

The drip monitoring sensor 1 of the present embodiment is not limited to the above-described configuration. The liquid column detection unit 50, the droplet detection unit 60, the amplification unit 70, and the notification unit 80 of the drip monitoring sensor 1 may be provided in, for example, an external device capable of communicating with the drip monitoring sensor 1. Further, as an example, the drip monitoring sensor and the external device capable of communicating with the drip monitoring sensor may be configured not to include the amplification unit 70.

Next, the details of the light guide unit 30 will be described. First, one problem that may occur when the light guide unit 30 is not provided will be described.

FIG. 5 is a diagram showing a main part of the drip monitoring sensor 1000 as a comparative example of the present embodiment. The drip monitoring sensor 1000 as a comparative example shown in FIG. 5 includes a light emitting unit 1010 and a light receiving unit 1020, but does not include the light guide unit 30 of the present embodiment. FIG. 5 shows the droplet V together with the light emitting unit 1010 and the light receiving unit 1020 of the drip monitoring sensor 1000. The light emitting unit 1010 shown in FIG. 5 includes three light emitting elements 1011a to 1011c. The light receiving unit 1020 shown in FIG. 5 includes five light receiving elements 1021a to 1021e. The number of light emitting elements and light receiving elements does not have to be the number shown in FIG. FIG. 5 shows the range of the directivity angles of the light rays emitted from the three light emitting elements 1011a to 1011c for convenience of explanation. Specifically, the range of the directivity angles of the light emitting elements 1011a and 1011c is indicated by a solid trapezoid. The range of the directional angle of the light emitting element 1011b is indicated by a two-dot chain line on the light receiving portion 1020 side of the droplet V, and is a region where the shadow of the droplet V is formed by the light of the light emitting element 1011b. Further, in FIG. 5, the light emitted from the light emitting element 1011b and transmitted through the droplet V is shown by the light ray R. FIG. 5 shows the traveling direction of the light ray R when the droplet V is a transparent liquid. When the droplet V is an opaque liquid, the light beam R does not pass through the droplet V and is mostly absorbed by the droplet V, forming a shadow of the droplet V with a higher contrast than in the case of the transparent liquid. .. That is, the amount of transmitted light of the droplet V by the light beam R differs depending on the transparency of the droplet V.

As shown in FIG. 5, the light emitted from the light emitting element 1011b irradiates the droplet V. As a result, a shadow of the droplet V is formed on the light receiving portion 1020 side of the droplet V. The light emitted from the light emitting element 1011b is received by the light receiving elements 1021b to 1021d in the range of the directivity angle when there is no droplet V. However, when the droplet V is a transparent liquid, as shown in FIG. 5, the light ray R emitted from the light emitting element 1011b and refracted by the droplet V is in the range of the original directional angle (see the range of the alternate long and short dash line). The light is received by all the light receiving elements 1021a to 1021e. That is, in the drip monitoring sensor 1000 as a comparative example shown in FIG. 5, the presence of the droplet V reduces the amount of light received from the light emitting element 1011b and received by the light receiving element 1021c. However, the amount of light received by the other light receiving elements 1021a, 1021b, 1021d and 1021e increases due to the refracted light refracted by the droplet V of the transparent liquid (see the light ray R in FIG. 5). Fluctuations in the total amount of light received per unit time are small. Further, the light emitted from the light emitting elements 1011a and 1011c on both sides directly reaches the region where the shadow of the droplet V is formed without being irradiated to the droplet V, and is received by the light receiving elements 1021b to 1021d. Therefore, in the drip monitoring sensor 1000 as a comparative example shown in FIG. 5, the contrast with the surroundings tends to be low even for the shadow formed on the light receiving portion 1020 side of the droplet V.

As described above, in the drip monitoring sensor 1000 as a comparative example shown in FIG. 5, it is difficult to detect a decrease in the amount of received light due to the shadow formed on the light receiving portion 1020 side of the droplet V.

FIG. 6 is a diagram showing changes in the total amount of light received per unit time received by the light receiving unit 1020 of the drip monitoring sensor 1000 as a comparative example shown in FIG. FIG. 6A shows a change in the total amount of light received per unit time of the light receiving unit 1020 caused by droplets V of an opaque liquid such as a fat emulsion. FIG. 6B shows a change in the total amount of light received per unit time of the light receiving unit 1020 caused by droplets V of a transparent liquid such as physiological saline. As shown in FIG. 6A, with respect to the opaque liquid droplet V, as described above, the light is absorbed by the droplet V, so that the total amount of light received by the light receiving unit 1020 per unit time decreases. .. On the other hand, as shown in FIG. 6B, with respect to the transparent liquid droplet V, as described above, the light refracted by the droplet V is received by the light receiving element in a wide range, so that the light receiving portion The total amount of light received per unit time of 1020 is unlikely to decrease. In particular, in a state where the light emitted from the light emitting unit 1010 irradiates the vicinity of the central plane including the center of the droplet V (see the range “S2” in FIG. 6B), the light is refracted by the droplet V. However, the light receiving elements 1021a to 1021e in the horizontal plane H are likely to receive light (see FIG. 5), and the total light receiving amount per unit time of the light receiving unit 1020 increases. That is, it is particularly difficult to detect a decrease in the amount of light received due to the shadow formed on the light receiving portion 1020 side of the droplet V. On the other hand, in a state where the light emitted from the light emitting unit 1010 does not irradiate the vicinity of the central plane including the center of the droplet V (see the ranges “S1” and “S3” in FIG. 6B), the light is light. Is easily refracted in the vertical direction (vertical direction) by the droplet V, and is unlikely to be received by the light receiving elements 1021a to 1021e in the horizontal plane H. That is, in the ranges “S1” and “S3” of FIG. 6B, the total amount of light received by the light receiving unit 1020 per unit time decreases. In other words, in the ranges “S1” and “S3” of FIG. 6B, it is easy to detect a decrease in the amount of light received due to the shadow formed on the light receiving portion 1020 side of the droplet V.

FIG. 7 is a diagram showing changes in the total amount of light received per unit time received by the light receiving unit 1020 of the drip monitoring sensor 1000 as a comparative example shown in FIG. FIG. 7 shows a case where the transparent liquid changes from the droplet state to the liquid column state and a case where the opaque liquid changes from the droplet state to the liquid column state. As shown in FIG. 7, in the opaque liquid, the total amount of light received by the light receiving unit 1020 per unit time when changing from the droplet state to the liquid column state is reduced from "m1" to "m2". .. On the other hand, as shown in FIG. 7, in the transparent liquid, when the liquid state changes from the droplet state to the liquid column state, the total amount of light received by the light receiving unit 1020 per unit time changes from "n1" to "n2". It has increased.

From the above, the inventor of the present application has obtained the following two findings.
(1) In the drip monitoring sensor 1000 as a comparative example shown in FIG. 5, the amount of light received by the light receiving unit 1020 is per unit time according to the transparency of the droplet V falling inside the drip tube 110 (see FIG. 1). The way the total amount of light received changes greatly differs (see FIG. 6).
(2) As a result, as shown in FIG. 7, when the liquid falling inside the drip tube 110 changes from the droplet state to the liquid column state, the total amount of light received by the light receiving unit 1020 per unit time is , In the case of a transparent liquid, it increases, and in the case of an opaque liquid, it decreases.

However, the transparency of the liquid used in the infusion line varies and is not constant. That is, when the transparency of the liquid falling inside the drip tube 110 is unknown, it is not possible to set a threshold value for detecting the change from the droplet state to the liquid column state.

As a result of diligent studies based on the above findings, the inventor of the present application shows that the difference in the increase or decrease in the total amount of light received per unit time of the light receiving portion when the state is changed from the droplet state to the liquid column state is the light received under a predetermined environment. We have come to recognize that it is likely to occur when using a part. The predetermined environment is an environment in which the light receiving unit 1020 easily receives the reflected light reflected by the liquid falling inside the drip tube 110 and the refracted light refracted by the liquid. That is, the above problem is solved by making the light receiving portion difficult to receive the reflected light and the refracted light, that is, a structure capable of detecting the "shadow" component of the liquid falling inside the drip tube 110.

Regarding this point, Patent Document 1 describes a configuration for detecting the above-mentioned "shadow" component of a liquid, but in order to obtain a high contrast that realizes this detection, irradiation is performed with only one light emitting element. It describes what to do. In such a configuration, the irradiation range of the irradiation light is limited, and there is a possibility that the droplet in the drip tube cannot be detected.

On the other hand, the drip monitoring sensor 1 shown in FIGS. 1 to 4 includes a light guide unit 30. Even if the light guide unit 30 includes a light emitting unit 10 capable of simultaneously irradiating the inside of the drip cylinder 110 with the irradiation light L1 from different positions in the circumferential direction of the drip cylinder 110, the inside of the drip cylinder 110 is dropped. It is possible to make it difficult for the light receiving unit 20 to receive the reflected light reflected by the liquid and the refracted light refracted by the liquid. This makes it easier to detect the "shadow" component of the falling liquid. Therefore, it is possible to realize a configuration in which the droplet state and the liquid column state of the liquid can be easily detected regardless of the transparency of the liquid falling inside the drip tube 110.

Specifically, regardless of the transparency of the liquid falling inside the drip tube 110, the total amount of received light per unit time received by the light receiving unit 20 when changing from the droplet state to the liquid column state is reduced. It is possible to realize the drip monitoring sensor 1 that changes as described above. The details will be described later (see FIGS. 20 and 21). Therefore, when the change from the droplet state to the liquid column state is detected by the change in the total received light amount by the light receiving unit 20 with the passage of time, it is not necessary to set a threshold value for the increase in the total received light amount, and the total received light is received. Only thresholds for volume reduction need to be set. This makes it possible to simplify the detection algorithm of the liquid column state.

As shown in FIG. 4, in the drip monitoring sensor 1 of the present embodiment, among the irradiation light L1 emitted from the light emitting unit 10 to the inside of the drip tube 110, the refracted light refracted by the falling liquid 116 which is a transparent liquid is generated. By providing the light guide unit 30, it becomes difficult for light to be received by other than the light receiving element 21d. In this way, by suppressing the scattered light reflected or refracted by the falling liquid 116 from being received by the light receiving unit 20, it becomes a "shadow" component of the falling liquid 116, that is, a shadow of the falling liquid 116. The light receiving unit 20 can be made easier to detect the decrease in the total light receiving amount generated in. As a result, as described above, the droplet state and the liquid column state of the falling liquid 116 can be easily detected regardless of the transparency of the falling liquid 116 falling inside the drip tube 110.

Further, as shown in FIG. 2, in a state where the drip tube 110 is housed in the storage space 2a, the shortest distance D1 from the light emitting portion 10 to the storage space 2a in the radial direction A of the drip tube 110 is the drip tube 110. It is shorter than the shortest distance D2 from the light receiving portion 20 to the accommodation space 2a in the radial direction A. By doing so, the light emitting unit 10 can be arranged close to the drip tube 110, and the useless irradiation light L1 that is not irradiated inside the drip tube 110 can be reduced. On the other hand, the light receiving unit 20 can be arranged away from the drip tube 110, and it is easy to secure the length of the light guide path 31 of the light guide unit 30. Therefore, the "shadow" component of the falling liquid 116, that is, the decrease in the total light receiving amount generated by the shadow of the falling liquid 116 can be detected more accurately. As a result, as described above, the droplet state and the liquid column state of the falling liquid 116 can be easily detected regardless of the transparency of the falling liquid 116 falling inside the drip tube 110.

Further, as shown in FIG. 4, the shortest distance D3 from the inlet opening 31a of the light guide path 31 of the light guide unit 30 of the present embodiment to the light receiving unit 20 is the entrance of the light guide path 31 of the light guide unit 30 of the present embodiment. It is longer than the maximum light input width W1 of the opening 31a. By doing so, it is possible to more accurately detect the decrease in the total amount of received light generated by the shadow of the falling liquid 116. Since the light guide portion 30 of the present embodiment is formed of a tubular body, the "maximum light input width W1" of the present embodiment is equal to the inner diameter of the light guide portion 30.

It is preferable that the inner diameter of the light guide portion 30 (maximum light input width W1) of the present embodiment is close to the outer diameter of the light receiving element 21. Since the outer diameter of the light receiving element is usually 1 to 3 mm, the maximum light input width W1 is preferably about 2 mm. Further, D3 / W1, which is the ratio of the shortest distance D3 to the maximum light input width W1, is preferably 2 or more, and particularly preferably 2 or more and 5 or less. By setting D3 / W1 in this range, the "shadow" component of the falling liquid 116 can be detected by using the light guide unit 30 having a size that does not pose a problem in actual use, and the droplet state and the liquid column of the falling liquid 116 can be detected. The state can be easily detected.

Hereinafter, an example of the detection process by the liquid column detection unit 50 and the droplet detection unit 60 will be described with reference to FIGS. 8 to 11. The light receiving signal output from the light receiving unit 20 to the liquid column detecting unit 50 and the droplet detecting unit 60 is detected as a different signal depending on whether the falling liquid 116 is in the liquid column state or the droplet state. However, regardless of whether the falling liquid 116 is in a liquid column state or a droplet state, the received light signal in each case changes in a complicated manner every minute time, so that the liquid column state can be detected with the received signal as it is. And it is not easy to detect the droplet state. Therefore, as described below, the liquid column detection unit 50 and the droplet detection unit 60 first calculate the moving interval integration of the amplitude of the received signal to detect the liquid column state and the droplet state. It can be converted into an easy form.

8 to 10 are diagrams for explaining a droplet state detection process by the droplet detection unit 60, specifically, a process of integrating the peak waveform of the received signal with the moving interval of the amplitude. FIG. 8 is a diagram showing an example of a received signal when the falling liquid 116 is a transparent liquid and is in a droplet state, and a period for integrating the moving interval of the amplitude. This light receiving signal correlates with the total amount of light received per unit time received by the light receiving unit 20. The integrated value Z (t) obtained by calculating the moving interval integration of the amplitude at time t on the received signal is expressed by the following mathematical formula (1).
Z (t) = (Yb-Y (t)) + (Yb-Y (t-1)) + (Yb-Y (tN-1)) ・ ・ ・ (1)
Here, Yb indicates the reference level of the input waveform, Y (t) indicates the amplitude at time t, and N indicates the number of samples of the integration interval T1 of the moving interval integration. This integration interval T1 is hereinafter referred to as “first period T1” for convenience of explanation. The integral value Z (t) of the moving interval integral correlates with the total flow rate of the falling liquid 116 in the most recent first period T1 at time t. The first period T1 is preferably about the same as the time width of a waveform (hereinafter, also referred to as “peak waveform”) including only the peak of the amplitude generated in the received signal by the falling liquid 116 in the droplet state.

9 (a) and 9 (b) are diagrams showing an example of a peak waveform generated in a received signal by the falling liquid 116 in a droplet state. Specifically, FIG. 9A is a light receiving signal detected when the falling liquid 116 is a droplet of an opaque liquid. FIG. 9B is a light receiving signal detected when the falling liquid 116 is a droplet of a transparent liquid. 10 (a) and 10 (b) are diagrams showing waveforms obtained by converting the peak waveforms shown in FIGS. 9 (a) and 9 (b) into moving section integral waveforms of amplitude. Both FIGS. 9 (a) and 9 (b) are peak waveforms having only an amplitude in the negative direction with respect to the reference level Yb. As described above, by providing the light guide unit 30 (see FIG. 4), even if the transparent liquid is a falling liquid 116, the received light signal can be a signal having only a negative amplitude (FIG. 9 (b). )reference). As shown in FIGS. 10 (a) and 10 (b), when the peak waveform of the received signal is converted into the moving interval integral waveform of the amplitude, the peak waveform has a large peak amplitude in the positive direction. The droplet detection unit 60 detects the droplet state when the moving section integral waveform includes a peak waveform whose amplitude is within a predetermined range and whose time width is within a predetermined range. In other words, the droplet detection unit 60 detects the droplet state when the light receiving signal includes a peak waveform whose amplitude is within a predetermined range and whose time width is within a predetermined range.

FIG. 11 is a diagram illustrating a liquid column state detection process by the liquid column detection unit 50. Specifically, FIG. 11 is a diagram showing changes in the total amount of light received by the light receiving unit 20 per unit time. The total amount of light received per unit time of the light receiving unit 20 is the section in which the falling liquid 116 is falling in a normal droplet state (section shown as “section 1” in FIG. 11) and the falling liquid 116 in a liquid column state. The section where the liquid is falling (the section indicated as "section 3" in FIG. 11) and the section where the falling liquid 116 is falling with an abnormally high flow rate of droplets between these two sections (the section "section 3" in FIG. 11). 2 ”) and the three sections show different tendencies.

As shown in FIG. 11, in the section 1 in which the falling liquid 116 is falling in a normal droplet state, a peak waveform having an amplitude within a predetermined range and a time width within a predetermined range is a received signal. , It is detected periodically with a time width within a predetermined range. In section 1, the above-mentioned droplet detection unit 60 is a normal liquid based on the first period T1 which is the time width of the peak waveform, the amplitude a1 of the peak waveform, and the time interval T2 between adjacent peak waveforms. Detect the drop condition. When the droplet detection unit 60 detects a normal droplet state in section 1, the liquid column detection unit 50 is the total amount per unit time of the light receiving unit 20 for detecting the liquid column state of the falling liquid 116. The reference level X of the amount of received light is updated. Specifically, in the example shown in FIG. 11, the liquid column detection unit 50 updates the reference level X every time the droplet detection unit 60 detects a normal droplet state in the section 1 (in FIG. 11). Updated in the order of "X1", "X2", "X3").

On the other hand, as shown in FIG. 11, in the section 2 in which the falling liquid 116 is falling in the state of droplets having an abnormally high flow rate, the above-mentioned droplet detection unit 60 has a time width of the peak waveform. A normal droplet state cannot be detected based on one period T1, the peak waveform amplitude a1, and the time interval T2 between adjacent peak waveforms. In the section 2, when the droplet detection unit 60 cannot detect a normal droplet state, the liquid column detection unit 50 receives the total light received per unit time of the light receiving unit 20 for detecting the liquid column state of the falling liquid 116. Do not update the quantity reference level X. That is, the last updated reference level X in section 1 is not changed (in FIG. 11, it is not changed from "X3").

When the total light receiving amount of the light receiving unit 20 drops by a predetermined amount Q or more over a predetermined time T3 or more with respect to the reference level X as a predetermined threshold value, the liquid column detecting unit 50 liquid drops the liquid 116. Detect the pillar state. The above "predetermined time T3" is preferably set in the range of 0.1 to 5 seconds. If the predetermined time T3 is shorter than 0.1 seconds, erroneous detection increases, and if it is longer than 5 seconds, a time delay until the liquid column state is detected occurs. Further, the above-mentioned "predetermined amount Q" is set to an applicable amount of change regardless of the transparency of the falling liquid 116. Therefore, the liquid column detection unit 50 does not detect the liquid column state of the falling liquid 116 in the above-mentioned sections 1 and 2.

As shown in FIG. 11, in the section 3 in which the falling liquid 116 is falling in the liquid column state, the above-mentioned droplet detection unit 60 has a first period T1, which is the time width of the peak waveform, and an amplitude a1 of the peak waveform. In addition, a normal droplet state cannot be detected based on the time interval T2 between adjacent peak waveforms. Therefore, also in the section 3, the reference level X last updated in the section 1 is not changed (in FIG. 11, it is not changed from “X3”). Further, in the section 3, the total light receiving amount of the light receiving unit 20 is lowered by a predetermined amount Q or more over a predetermined time T3 or more with respect to the reference level X as a predetermined threshold value, so that the liquid column detecting unit 50 Detects the liquid column state of the falling liquid 116.

As described above, the liquid column detection unit 50 and the droplet detection unit 60 of the present embodiment can detect the liquid column state and the droplet state of the falling liquid 116.

(Second Embodiment)
Next, the drip monitoring sensor 201 as the second embodiment will be described with reference to FIG. FIG. 12 is a diagram showing a main part of the drip monitoring sensor 201. The drip monitoring sensor 201 is different from the drip monitoring sensor 1 of the first embodiment in that it includes a light guide unit 40 arranged between the drip cylinder 110 and the light emitting unit 10. The other configuration of the drip monitoring sensor 201 is the same as that of the drip monitoring sensor 1 described above. Therefore, here, among the drip monitoring sensors 201, the differences from the drip monitoring sensor 1 will be mainly described, and the description of the common configuration will be omitted.

Hereinafter, in order to distinguish between the light guide unit 30 arranged between the drip tube 110 and the light receiving unit 20, and the light guide unit 40 arranged between the drip tube 110 and the light emitting unit 10, description thereof will be described. For convenience, the light guide unit 30 is referred to as a "first light guide unit 30", and the light guide unit 40 is referred to as a "second light guide unit 40".

As shown in FIG. 12, the second light guide unit 40 internally partitions a second light guide path 41 that limits the irradiation light L1 emitted from the light emitting unit 10 to the inside of the drip tube 110. By providing such a second light guide unit 40, it is possible to reduce the useless irradiation light L1 emitted to the inside of the drip tube 110.

Further, the second light guide unit 40 is configured so as not to transmit the irradiated light and not to totally reflect the irradiated light. For example, a microconcavo-convex structure that diffusely reflects the irradiated light may be formed on the outer surface and the inner surface of the second light guide unit 40. Further, the second light guide unit 40 may be configured to be able to absorb a part or all of the irradiated light, for example, it may be formed of a black opaque resin or covered with a black paint. .. The second light guide unit 40 of the present embodiment is composed of a tubular body that internally partitions the second light guide path 41. The second light guide unit 40 of the present embodiment has an inlet opening of the second light guide path 41 through which the irradiation light L1 can enter the second light guide path 41 on the end surface on one end side arranged so as to face the light emitting unit 10. It divides 41a. Further, the second light guide unit 40 of the present embodiment is a second light guide path capable of emitting light from the second light guide path 41 toward the drip cylinder 110 on the other end surface arranged facing the drip cylinder 110. The outlet opening 41b of 41 is partitioned.

The length of the first light guide path 31 in the extending direction (axial length in the present embodiment) is longer than the length of the second light guide path 41 in the extending direction (axial length in the present embodiment). By doing so, the light emitting unit 10 can be arranged closer to the drip tube 110 than the light receiving unit 20, and unnecessary irradiation light L1 that is not irradiated inside the drip tube 110 can be reduced. On the other hand, the light receiving unit 20 can be arranged farther from the drip tube 110 than the light emitting unit 10, and it is easy to secure the length of the light guide path 31 of the light guide unit 30. Therefore, the "shadow" component of the falling liquid 116, that is, the decrease in the total light receiving amount generated by the shadow of the falling liquid 116 can be detected more accurately. As a result, as described above, the droplet state and the liquid column state of the falling liquid 116 can be easily detected regardless of the transparency of the falling liquid 116 falling inside the drip tube 110.

(Third Embodiment)
Next, with reference to FIG. 13, the drip monitoring sensor 301 as the third embodiment will be described. FIG. 13 is a diagram showing a main part of the drip monitoring sensor 301. The drip monitoring sensor 301 is different from the drip monitoring sensor 1 of the first embodiment in the configurations of the light emitting unit and the light receiving unit. The other configuration of the drip monitoring sensor 301 is the same as that of the drip monitoring sensor 1 described above. Therefore, here, among the drip monitoring sensors 301, the differences from the drip monitoring sensor 1 will be mainly described, and the description of the common configuration will be omitted.

The light emitting unit 310 includes a light emitting element 311 and an optical element 312 capable of converting the light emitted from the light emitting element 311 into parallel light. In this drip monitoring sensor 301, the parallel light converted by the optical element 312 becomes the irradiation light L1 that is applied to the drip tube 110.

The light emitting unit 310 shown in FIG. 13 includes only one light emitting element 311 and only one optical element 312, but is not limited to this configuration, and includes a plurality of light emitting elements and a plurality of optical elements. It may be a light emitting unit to be provided.

The light emitting element 311 can be configured by, for example, an LED (Light Emitting Diode), a laser diode, or the like. As shown in FIG. 13, the optical element 312 can transmit the light incident from one light emitting element 311 and convert it into parallel light as the irradiation light L1, for example, a cylindrical lens, a spherical lens, and a Fresnel lens. Etc. can be configured. Alternatively, the optical element 312 may be composed of, for example, a Fresnel mirror, a parabolic mirror, or the like, which can reflect the light incident from one light emitting element 311 and convert it into parallel light as the irradiation light L1. can. The light ray R1 of the example shown in FIG. 13 is a light ray of parallel light as the irradiation light L1 converted by the optical element 312.

The light receiving unit 320 includes a light receiving element 321 and an optical element 322 capable of condensing the light received by the light receiving element 321. In this drip monitoring sensor 301, the irradiation light L1 emitted from the light emitting unit 310 to the inside of the drip cylinder 110 can be focused on the light receiving element 321 by the optical element 322.

The light receiving unit 320 shown in FIG. 13 includes only one light receiving element 321 and only one optical element 322, but is not limited to this configuration, and includes a plurality of light receiving elements and a plurality of optical elements. It may be a light receiving unit provided.

The light receiving element 321 can be configured by, for example, a phototransistor, a photodiode, or the like. As shown in FIG. 13, the optical element 322 can be composed of, for example, a cylindrical lens, a spherical lens, a Fresnel lens, or the like, which can transmit incident light and collect it on the light receiving element 321. Alternatively, the optical element 322 can be configured by, for example, a Fresnel mirror, a parabolic mirror, or the like, which can reflect the incident light and condense it on the light receiving element 321. The light ray R2 of the example shown in FIG. 13 is a light ray showing the transmitted light transmitted through the falling liquid 116 before being converted by the optical element 322. In the example shown in FIG. 13, among the light rays R2, the light rays that reach the light receiving element 321 through the first light guide path 31 of the first light guide unit 30 are focused on the light receiving element 321 by the optical element 322.

(Fourth Embodiment)
Next, the drip monitoring sensor 401 as the fourth embodiment will be described with reference to FIGS. 14 to 16. FIG. 14 is a front view of the drip monitoring sensor 401 mounted on the drip tube 110. FIG. 15 is a block diagram showing the configuration of the drip monitoring sensor 401. In FIG. 15, for convenience of explanation, the first light guide unit 30 is also shown. FIG. 16 is a diagram illustrating an example of a liquid column state determination process by the drip monitoring sensor 401. Since the drip monitoring sensor 401 has many points in common with the drip monitoring sensor 1 of the first embodiment, the differences from the drip monitoring sensor 1 will be mainly described below, and the common points will be omitted.

As shown in FIGS. 14 and 15, the drip monitoring sensor 401 includes a light emitting unit 10, a light receiving unit 20, a first light guide unit 30, a liquid column detection unit 50, a droplet detection unit 60, and an amplification unit. A 70, a notification unit 80, a housing 2, a liquid column determination unit 155, a droplet determination unit 165, and an external light detection unit 190 are provided.

The light receiving unit 20 includes an upper light receiving unit 120a and a lower light receiving unit 120b installed at different positions in the vertical direction. The upper light receiving unit 120a and the lower light receiving unit 120b each include at least one light receiving element. As shown in FIG. 14, the upper light receiving unit 120a is installed above the lower light receiving unit 120b in the vertical direction. That is, the light receiving unit 20 includes at least two light receiving elements installed at different positions in the vertical direction.

As shown in FIG. 15, the amplification unit 70 includes an upper amplification unit 170a and a lower amplification unit 170b. The upper amplification unit 170a is composed of, for example, an amplifier circuit or the like, amplifies the light receiving signal from the upper light receiving unit 120a, and outputs the light receiving signal to the upper liquid column detection unit 150a and the upper droplet detection unit 160a, which will be described later. The lower amplification unit 170b is composed of, for example, an amplifier circuit or the like, amplifies the light reception signal from the lower light receiving unit 120b, and outputs the signal to the lower liquid column detection unit 150b and the lower droplet detection unit 160b, which will be described later.

As shown in FIG. 15, the liquid column detection unit 50 includes an upper liquid column detection unit 150a and a lower liquid column detection unit 150b. The upper liquid column detection unit 150a can detect the state of the liquid column of the liquid based on the light receiving signal from the upper light receiving unit 120a. When the upper liquid column detection unit 150a detects the liquid column state, the upper liquid column detection unit 150a outputs the detection result to the liquid column determination unit 155. The lower liquid column detection unit 150b can detect the state of the liquid column of the liquid based on the light receiving signal from the lower light receiving unit 120b. When the lower liquid column detection unit 150b detects the liquid column state, the lower liquid column detection unit 150b outputs the detection result to the liquid column determination unit 155. The details of the upper liquid column detection unit 150a and the lower liquid column detection unit 150b are the same as those of the liquid column detection unit 50 of the first embodiment, and thus the description thereof will be omitted.

The liquid column determination unit 155 drops the liquid in the liquid column state based on the detection result of the liquid column state from the upper liquid column detection unit 150a and the detection result of the liquid column state from the lower liquid column detection unit 150b. Determine if it is. In the case of a configuration in which the liquid column state is detected by only one liquid column detection unit, for example, a droplet that falls in the drip tube 110, jumps up by the stored liquid 117, adheres to the inner surface of the drip tube 110, and does not fall is detected. By doing so, it may be erroneously detected that the liquid is falling in the state of a liquid column. Therefore, in the present embodiment, the above-mentioned erroneous detection can be suppressed by executing the detection operation of the liquid column state of the liquid at different positions in the vertical direction. Specifically, in the liquid column determination unit 155, when the upper liquid column detection unit 150a detects the liquid column state and the lower liquid column detection unit 150b detects the liquid column state, the liquid is in the liquid column state. Judge that it is falling. The method for each of the upper liquid column detecting unit 150a and the lower liquid column detecting unit 150b to detect the liquid column state is the same as that of the liquid column detecting unit 50 (see FIG. 3 and the like) of the first embodiment.

FIG. 16A shows an upper light receiving state in the case where the liquid does not actually fall in the liquid column state and the lower light receiving portion 120b detects a droplet that adheres to the inner surface of the drip tube 110 and does not fall. It is a figure which shows the change of the light receiving amount of the part 120a and the lower light receiving part 120b. Based on the amount of irradiation light received by the upper light receiving unit 120a shown by the broken line in FIG. 16A, the upper liquid column detecting unit 150a cannot detect the liquid column state. On the other hand, based on the amount of irradiation light received by the lower light receiving unit 120b shown by the solid line in FIG. 16A, the lower liquid column detecting unit 150b detects the liquid column state. Therefore, the liquid column determination unit 155 cannot detect the liquid column state by the upper liquid column detection unit 150a, and therefore even when the lower liquid column detection unit 150b detects the liquid column state (when erroneous detection is performed). Even if there is, it is not determined that the liquid is falling in the state of a liquid column.

On the other hand, FIG. 16B is a diagram showing changes in the amount of light received by the upper light receiving unit 120a and the lower light receiving unit 120b when the liquid is actually falling in a liquid column state. Based on the amount of irradiation light received by the upper light receiving unit 120a shown by the broken line in FIG. 16B, the upper liquid column detecting unit 150a detects the liquid column state. Further, based on the amount of irradiation light received by the lower light receiving unit 120b shown by the solid line in FIG. 16B, the lower liquid column detecting unit 150b detects the liquid column state. Therefore, in the liquid column determination unit 155, since the upper liquid column detection unit 150a detects the liquid column state and the lower liquid column detection unit 150b detects the liquid column state, the liquid falls in the liquid column state. It is determined that it is.

As shown in FIG. 15, the droplet detection unit 60 includes an upper droplet detection unit 160a and a lower droplet detection unit 160b. The upper droplet detection unit 160a can detect the liquid droplet state based on the light receiving signal from the upper light receiving unit 120a. When the upper droplet detection unit 160a detects the droplet state, the upper droplet detection unit 160a outputs the detection result to the droplet determination unit 165. The lower droplet detection unit 160b can detect the liquid droplet state based on the light receiving signal from the lower light receiving unit 120b. When the lower droplet detection unit 160b detects the droplet state, the lower droplet detection unit 160b outputs the detection result to the droplet determination unit 165. The details of the upper droplet detection unit 160a and the lower droplet detection unit 160b are the same as those of the droplet detection unit 60 of the first embodiment, and thus the description thereof will be omitted.

In the droplet determination unit 165, the liquid drops in the droplet state based on the detection result of the droplet state from the upper droplet detection unit 160a and the detection result of the droplet state from the lower droplet detection unit 160b. Determine if it is. In the case of a configuration in which the droplet state is detected by only one droplet detection unit, for example, the liquid drops in the droplet state by detecting the droplets that have fallen in the drip tube 110 and bounced off by the stored liquid 117. It may be falsely detected as being. Therefore, in the present embodiment, the above-mentioned erroneous detection can be suppressed by executing the detection operation of the liquid droplet state at different positions in the vertical direction. Specifically, the droplet determination unit 165 detects the lower droplet within a predetermined time after the upper droplet detection unit 160a detects the droplet state and the upper droplet detection unit 160a detects the droplet state. When the unit 160b detects the droplet state, it is determined that the liquid is falling in the droplet state. The method in which the upper droplet detection unit 160a and the lower droplet detection unit 160b each detect the droplet state is the same as that of the droplet detection unit 60 (see FIG. 3 and the like) of the first embodiment.

Here, it is preferable to confirm the identity between the liquid in the droplet state detected by the upper droplet detection unit 160a and the liquid in the droplet state detected by the lower droplet detection unit 160b. Whether or not the liquids detected by the upper droplet detection unit 160a and the lower droplet detection unit 160b are the same is determined to have a degree of similarity equal to or higher than a predetermined value by pattern recognition or the like of the waveform of the received signal. It can be determined based on.

The liquid column determination unit 155 and the droplet determination unit 165 read, for example, a storage device that stores various information and programs, and a predetermined information and program among various information and programs stored in the storage device. This is composed of a processor or the like that realizes a predetermined function. The storage device, processor, and the like constituting the liquid column determination unit 155 and the droplet determination unit 165 include an upper liquid column detection unit 150a, a lower liquid column detection unit 150b, an upper droplet detection unit 160a, or a lower droplet detection unit 160b. It may be a member common to the storage device, the processor, or the like constituting the above, or it may be a separate member.

Further, the light receiving unit 20 of the present embodiment may have an external light receiving unit 120c capable of receiving external light. When the liquid column state is detected by each of the upper liquid column detection unit 150a and the lower liquid column detection unit 150b described above, the upper liquid column detection unit 150a and the lower liquid column detection are caused by a sudden change in external light due to opening and closing of a curtain or the like. The part 150b may detect the liquid column state at the same time. Therefore, even when the liquid column state does not actually occur, there is a possibility that the liquid column determination unit 155 erroneously determines that the liquid is falling in the liquid column state due to a sudden change in the external light. There is. On the other hand, the liquid column determination unit 155 of the present embodiment determines whether or not the liquid is falling in the liquid column state based on the change in the amount of external light received by the external light receiving unit 120c. .. Specifically, in the liquid column determination unit 155 of the present embodiment, the upper liquid column detection unit 150a detects the liquid column state, and the lower liquid column detection unit 150b detects the liquid column state. However, if the change in the amount of light received by the external light receiving unit 120c immediately before is equal to or greater than a predetermined threshold value, it is not determined that the liquid is falling in the liquid column state. On the contrary, in the liquid column determination unit 155 of the present embodiment, the upper liquid column detection unit 150a detects the liquid column state, the lower liquid column detection unit 150b detects the liquid column state, and the external light immediately before. When the change in the amount of light received by the light receiving unit 120c is less than a predetermined threshold value, it is determined that the liquid is falling in a liquid column state. Here, the change in the amount of light received by the external light receiving unit 120c should be determined within a predetermined time (for example, within several seconds) from the timing when the upper liquid column detecting unit 150a and the lower liquid column detecting unit 150b detect the liquid column state. Just do it. Whether or not the change in the amount of received light received by the external light receiving unit 120c is equal to or greater than a predetermined threshold value may be determined by, for example, the external light detecting unit 190 configured by a processor or the like. The determination result by the external light detection unit 190 is output to the liquid column determination unit 155.

In the present embodiment, the external light receiving unit 120c is provided separately from the upper light receiving unit 120a and the lower light receiving unit 120b, but either one of the upper light receiving unit 120a and the lower light receiving unit 120b also serves as the external light receiving unit 120c. It may be configured.

In the present embodiment, the light emitting unit 10 includes two light emitting units (upper light emitting unit and lower light emitting unit) installed at different positions in the vertical direction corresponding to the upper light receiving unit 120a and the lower light receiving unit 120b. May be good. As a result, the amount of light received by each of the upper light receiving unit 120a and the lower light receiving unit 120b can be increased.

Similar to the first embodiment, the droplet detection unit 60 of the present embodiment has a first period T1 (see FIG. 11) which is the time width of the peak waveform, an amplitude a1 of the peak waveform (see FIG. 11), and an adjacent portion. A normal droplet state is detected based on the time interval T2 (see FIG. 11) between peak waveforms. Further, in the droplet detection unit 60 of the present embodiment, in addition to these, a normal droplet state is obtained based on the time interval which is the difference between the detection times of the falling liquid 116 of the upper light receiving unit 120a and the lower light receiving unit 120b. It is being detected.

Next, the outline of the confirmation experiment for confirming the effect of the first light guide unit 30 and the second light guide unit 40 will be described. FIG. 17 is a diagram showing an outline of the experimental system of the confirmation experiment. As shown in FIG. 17, the light emitting unit 10 used in this confirmation experiment has seven light emitting elements 11a to 11g arranged in parallel at intervals of 2 mm. The seven light emitting elements 11a to 11g are all composed of the same LED. FIG. 18A is a diagram showing the emission characteristics of the seven light emitting elements 11a to 11g. The central rays of light emitted from each of the seven light emitting elements 11a to 11g correspond to the angle "0 °" in FIG. 18A. Further, as shown in FIG. 17, the light receiving unit 20 used in this confirmation experiment has seven light receiving elements 21a to 21g arranged in parallel at intervals of 2 mm. The seven light receiving elements 21a to 21g are all composed of the same phototransistor. FIG. 18B is a diagram showing incident characteristics of the seven light receiving elements 21a to 21g. The central ray of light emitted by each of the seven light receiving elements 21a to 21g corresponds to the angle "0 °" in FIG. 18B.

In this confirmation experiment, a tubular body having an inner diameter of 1.7 mm is used as the first light guide portion 30. In this confirmation experiment, when the first light guide unit 30 is not arranged, when a tubular body having an axial length (length of the light guide path) of 3.5 mm is arranged as the first light guide unit 30, and when the first light guide unit 30 is arranged. When a tubular body having an axial length of 7 mm was arranged as the light guide unit 30, three patterns were verified.

Further, in this confirmation experiment, a tubular body having an inner diameter of 1.7 mm is used as the second light guide portion 40. In this confirmation experiment, two patterns were verified, one in which the second light guide unit 40 was not arranged and the other in which a tubular body having an axial length of 2.5 mm was arranged as the second light guide unit 40.

In this confirmation experiment, a 20-drop / mL drip tube is used.

FIG. 19 is a diagram showing a difference in the amount of light received by the light receiving unit 20 depending on the length of the tubular body as the first light guide unit 30. FIG. 19A is a diagram showing a change in the amount of light received by the light receiving unit 20 due to droplets of an opaque liquid such as a fat emulsion. As shown in FIG. 19 (a), when the first light guide unit 30 is provided (broken line and solid line in FIG. 19 (a)), the case where the first light guide unit 30 is not provided (FIG. 19 (a)). Compared with the alternate long and short dash line), the decrease in the amount of light received by the light receiving unit 20 based on the droplets of the opaque liquid can be detected more easily. In other words, the light receiving unit 20 is less likely to receive scattered light such as reflected light or refracted light by the first light guide unit 30, and can detect the "shadow" of the droplet more accurately. Further, when the axial length of the first light guide unit 30 is 7 mm (solid line in FIG. 19 (a)), the axial length of the first light guide unit 30 is 3.5 mm (FIG. 19 (a)). ), The decrease in the amount of light received by the light receiving unit 20 based on the droplets of the opaque liquid can be detected more easily. That is, by increasing the axial length of the first light guide unit 30, the light receiving unit 20 is less likely to receive scattered light such as reflected light or refracted light. As a result, the "shadow" of the droplet can be detected more accurately.

FIG. 19B is a diagram showing a change in the amount of light received by the light receiving unit 20 due to droplets of a transparent liquid such as physiological saline. As shown in FIG. 19 (b), when the first light guide unit 30 is provided (broken line and solid line in FIG. 19 (b)), the case where the first light guide unit 30 is not provided (FIG. 19 (b)). Compared with the alternate long and short dash line), the decrease in the amount of light received by the light receiving unit 20 based on the droplets of the transparent liquid can be detected more easily. In other words, even if the light receiving unit 20 is a droplet of a transparent liquid, the first light guide unit 30 makes it difficult for the light receiving unit 20 to receive scattered light such as reflected light or refracted light, and makes the “shadow” of the droplet more difficult. It will be possible to detect with high accuracy. Further, when the axial length of the first light guide unit 30 is 7 mm (solid line in FIG. 19B), the axial length of the first light guide unit 30 is 3.5 mm (FIG. 19 (b)). ), The decrease in the amount of light received by the light receiving unit 20 based on the droplets of the transparent liquid can be detected more easily. That is, by increasing the axial length of the first light guide unit 30, the light receiving unit 20 is less likely to receive scattered light such as reflected light or refracted light. As a result, the "shadow" of the droplet can be detected more accurately.

As described above, it can be seen that by providing the first light guide unit 30, it becomes easier to detect the "shadow" of the liquid regardless of the transparency of the liquid. That is, by providing the first light guide unit 30, the light receiving unit 20 is less likely to receive scattered light such as reflected light or refracted light even if the liquid is a transparent liquid. As a result, it is possible to suppress the occurrence of a problem (see FIG. 6B) in which the amount of light received by the light receiving unit 20 is increased by the liquid.

FIG. 20 is a diagram showing a change in the amount of light received by the light receiving unit 20 when the opaque liquid changes from a droplet state to a liquid column state. FIG. 20A shows a case where the first light guide unit 30 is not provided. FIG. 20B shows a case where a tubular body having an axial length of 3.5 mm is provided as the first light guide portion 30. FIG. 20C shows a case where a tubular body having an axial length of 7 mm is provided as the first light guide unit 30. As shown in FIGS. 20 (a) to 20 (c), when an opaque liquid is used as the liquid, the amount of light received by the light receiving unit 20 decreases when the liquid changes from a droplet state to a liquid column state. You can see that it does.

FIG. 21 is a diagram showing a change in the amount of light received by the light receiving unit 20 when the transparent liquid changes from a droplet state to a liquid column state. FIG. 21A shows a case where the first light guide unit 30 is not provided. FIG. 21B shows a case where a tubular body having an axial length of 3.5 mm is provided as the first light guide unit 30. FIG. 21C shows a case where a tubular body having an axial length of 7 mm is provided as the first light guide unit 30. As shown in FIG. 21A, when a transparent liquid is used as the liquid, the amount of light received by the light receiving unit 20 when the liquid changes from the droplet state to the liquid column state without the first light guide unit 30. Little decreases and may increase in some cases. On the other hand, as shown in FIGS. 21 (b) and 21 (c), when a transparent liquid is used as the liquid, the liquid is changed from the droplet state to the liquid by providing the first light guide unit 30. It can be seen that the amount of light received by the light receiving unit 20 decreases when the state changes to the column state.

As described above, by providing the first light guide unit 30, it becomes easier to detect the "shadow" of the liquid regardless of the transparency of the liquid (see FIG. 19). As a result, regardless of the transparency of the liquid, the change from the liquid droplet state to the liquid column state can be detected by the same tendency of the light receiving amount of the light receiving unit 20 decreasing (see FIGS. 20 and 21). As described above, if the first light guide unit 30 is not provided, whether or not the amount of light received by the light receiving unit 20 decreases when the liquid changes from the droplet state to the liquid column state depends on the transparency of the liquid. (See Fig. 7). That is, if the transparency of the liquid used is unknown, the change from the droplet state to the liquid column state cannot be detected. On the other hand, by providing the first light guide unit 30, the amount of light received by the light receiving unit 20 decreases when the liquid changes from the droplet state to the liquid column state regardless of the transparency of the liquid. That is, by providing the first light guide unit 30, the change from the liquid droplet state to the liquid column state is detected by the same tendency of the light receiving amount in the light receiving unit 20 decreasing regardless of the transparency of the liquid. It becomes possible.

FIG. 22A is a diagram showing a change in the amount of light received by the light receiving unit 20 due to droplets of a transparent liquid such as physiological saline. As shown in FIG. 22A, when the second light guide unit 40 is provided (solid line in FIG. 22A), the second light guide unit 40 is not provided (broken line in FIG. 22A). It can be seen that the amount of light received by the light receiving unit 20 based on the droplets of the transparent liquid is slightly reduced as compared with the above. Here, a tubular body having an axial length of 2.5 mm is used as the second light guide unit 40, but the amount of light received by the light receiving unit 20 can be further reduced by increasing the axial length. Can be done. However, as described above, it can be seen that the decrease in the amount of light received by the light receiving unit 20 is more affected by the presence or absence of the first light guide unit 30 than by the presence or absence of the second light guide unit 40.

FIG. 22B is a diagram showing a change in the amount of light received by the light receiving unit 20 when the transparent liquid changes from a droplet state to a liquid column state. The broken line in FIG. 22B is a case where the second light guide unit 40 is not provided. The solid line in FIG. 22B is a case where a tubular body having an axial length of 2.5 mm is provided as the second light guide portion 40. As shown in FIG. 22 (b), by providing the second light guide unit 40, the amount of light received changes when the liquid changes from the droplet state to the liquid column state (from "o1" in FIG. 22 (b)). The change (change to "o2") can be made larger than the change when the second light guide unit 40 is not provided (change from "p1" to "p2" in FIG. 22B). As a result, it becomes easier to detect the change from the liquid droplet state to the liquid column state.

The drip monitoring sensor according to the present disclosure is not limited to the configuration specified in each of the above-described embodiments, and can be variously modified without departing from the gist of the invention described in the claims. For example, the light emitting unit 10 of the first embodiment and the light receiving unit 320 of the third embodiment may be combined to form an optical system. Further, the optical system may be formed by combining the light emitting unit 310 of the third embodiment and the light receiving unit 20 of the first embodiment. In addition to this, for example, the functions included in each member, each part, each step, etc. can be rearranged so as not to be logically inconsistent, and a plurality of members, parts, steps, etc. can be combined into one. Alternatively, it can be divided.

The present disclosure relates to a drip monitoring sensor.

1, 201, 301, 401: Drip monitoring sensor 2: Housing 2a: Containment space 10: Light emitting unit 11, 11a to 11g: Light emitting element 20: Light receiving unit 21, 21a to 21g: Light receiving element 30: First light guide unit 31 : First light guide path 31a: Inlet opening 31b: Outlet opening 40: Second light guide unit 41: Second light guide path 41a: Inlet opening 41b: Outlet opening 50: Liquid column detection unit 60: Droplet detection unit 70: Amplification unit 80: Notification unit 100: Infusion device 101: Infusion container 102: Connector 103: Infusion tube 104: Clamp 105: Infusion pump 110: Intravenous tube 111: Infusion unit 112: Discharge unit 113: Infusion chamber 114: Peripheral wall portion 116: Infusion liquid 117: Stored liquid 120a: Upper light receiving unit 120b: Lower light receiving unit 120c: External light receiving unit 150a: Upper liquid column detection unit 150b: Lower liquid column detection unit 155: Liquid column determination unit 160a: Upper droplet detection unit 160b: Lower Droplet detection unit 165: Droplet determination unit 170a: Upper amplification unit 170b: Lower amplification unit 190: External light detection unit 310: Light emitting unit 311: Light emitting element 312: Optical element 320: Light receiving unit 321: Light receiving element 322: Optical element 1000: Intravenous monitoring sensor 1010 as a comparative example: Light emitting unit 1011a to 1011c: Light emitting element 1020: Light receiving unit 1021a to 1021e: Light receiving element A: Intravenous tube radial direction B: Intravenous tube circumferential direction D1: Intravenous tube radial direction The shortest distance from the light emitting part to the accommodation space D2: The shortest distance from the light receiving part to the accommodation space in the radial direction of the drip tube D3: The shortest distance H from the inlet opening of the first light guide path of the first light guide part to the light receiving part : Horizontal plane L1: Irradiation light R, R1, R2: Ray V: Droplet W1: Maximum incoming light width

Claims (16)

It is a drip monitoring sensor that can be attached to the drip tube and monitors the liquid falling inside the drip tube.
A light emitting unit that is arranged outside the drip tube in the radial direction and can simultaneously irradiate the inside of the drip tube with irradiation light from different positions in the circumferential direction of the drip tube.
A light receiving unit that is arranged to face the light emitting unit with the drip tube in between and can receive the irradiation light, and a light receiving unit that can receive the irradiation light.
A drip monitoring sensor including a light guide portion that is arranged between the drip cylinder and the light receiving portion and internally partitions a light guide path that limits the irradiation light received by the light receiving portion. A housing for holding the light emitting portion and the light receiving portion is provided.
The housing partitions a storage space that can accommodate the drip tube.
In a state where the drip tube is housed in the storage space, the shortest distance from the light emitting portion in the radial direction of the drip tube to the storage space is from the light receiving part in the radial direction of the drip tube to the storage space. The drip monitoring sensor according to claim 1, which is shorter than the shortest distance of. An inlet opening of the light guide path through which the irradiation light can enter the light guide path is defined on an end surface of the light guide portion arranged so as to face the drip tube.
The drip monitoring sensor according to claim 1 or 2, wherein the shortest distance from the entrance opening of the light guide path to the light receiving portion is longer than the maximum light entry width of the entrance opening of the light guide path. When the light guide path is the first light guide path and the light guide portion is the first light guide portion, the light guide path is arranged between the drip cylinder and the light emitting portion, and the light emitting portion irradiates the inside of the drip cylinder. The drip monitoring sensor according to any one of claims 1 to 3, further comprising a second light guide portion that internally partitions the second light guide path that limits the irradiation light. The drip monitoring sensor according to claim 4, wherein the length of the first light guide path is longer than the length of the second light guide path. The drip monitoring sensor according to any one of claims 1 to 5, wherein the light emitting unit includes a plurality of light emitting elements arranged in the same horizontal plane and having parallel central rays of light to be emitted. The light emitting unit
Light emitting element and
The drip monitoring sensor according to any one of claims 1 to 5, further comprising an optical element capable of converting light emitted from the light emitting element into parallel light. The drip monitoring sensor according to any one of claims 1 to 7, wherein the light receiving unit includes a plurality of light receiving elements arranged in the same horizontal plane and having parallel central rays of the received light. The light receiving part is
With the light receiving element
The drip monitoring sensor according to any one of claims 1 to 7, further comprising an optical element capable of condensing light received by the light receiving element. The drip monitoring sensor according to any one of claims 1 to 9, further comprising a liquid column detecting unit that detects a liquid column state of the liquid based on a change in the amount of received irradiation light received by the light receiving unit. .. The liquid column detecting unit detects the liquid column state of the liquid when the received amount of the irradiation light received by the light receiving unit decreases by a predetermined amount or more for a predetermined time or more with respect to a predetermined threshold value. The drip monitoring sensor according to claim 10. The drip monitoring sensor according to claim 10 or 11, wherein the light receiving unit includes an upper light receiving unit and a lower light receiving unit installed at different positions in the vertical direction. The liquid column detection unit is
An upper liquid column detection unit that detects the state of the liquid column of the liquid based on a change in the amount of light received by the upper light receiving unit.
A lower liquid column detecting unit for detecting a liquid column state of the liquid based on a change in the amount of received irradiation light received by the lower light receiving unit is provided.
When the upper liquid column detection unit detects the liquid column state and the lower liquid column detection unit detects the liquid column state, it is determined that the liquid is falling in the liquid column state. The drip monitoring sensor according to claim 12, further comprising a determination unit. The light receiving unit includes an external light receiving unit capable of receiving external light.
The drip according to claim 13, wherein the liquid column determining unit determines whether or not the liquid is falling in the liquid column state based on a change in the amount of external light received by the external light receiving unit. Surveillance sensor. The drip monitoring sensor according to any one of claims 1 to 14, further comprising a droplet detection unit that detects a droplet state of the liquid based on a change in the amount of received irradiation light received by the light receiving unit. .. The light receiving unit includes an upper light receiving unit and a lower light receiving unit installed at different positions in the vertical direction.
The droplet detection unit
An upper droplet detection unit that detects a droplet state of the liquid based on a change in the amount of light received by the upper light receiving unit.
A lower droplet detecting unit that detects a droplet state of the liquid based on a change in the amount of received irradiation light received by the lower light receiving unit is provided.
When the upper droplet detection unit detects the droplet state and the lower droplet detection unit detects the droplet state within a predetermined time after the upper droplet detection unit detects the droplet state. The drip monitoring sensor according to claim 15, further comprising a droplet determination unit that determines that the liquid is falling in a droplet state.

Images