Drip monitoring sensor

Abstract

A drip monitoring sensor 1 comprises a droplet detection unit 10 for detecting a droplet 60 falling inside a drip chamber 50. An optical axis P1 of first detection light, which linearly connects a droplet detection light-emitting unit 11 and a droplet detection light-receiving unit 12 of the droplet detection unit 10, intersects with the falling path F of droplets. Furthermore, the drip monitoring sensor 1 is provided with a drip tube fogging detection unit 20. Moreover, an optical axis P2 of second detection light, which linearly connects a fogging detection light-emitting unit 21 and a fogging detection light-receiving unit 22, does not intersect with the droplet falling path F and the optical axis P1 of first detection light.

Description

Infusion monitoring sensor

[0001] The present invention relates to a drip monitoring sensor that can be attached to a drip cylinder and monitors droplets falling inside the drip cylinder.

[0002] Various drip monitoring sensors for monitoring droplets falling inside a drip tube have been proposed. For example, Patent Document 1 (JP 2014-204897 A) discloses a technique in which a plurality of light-emitting elements arranged around the drip tube irradiate light toward the drip tube, and droplets are detected based on changes in the amount of light received by a light-receiving element that receives the light.

[0003] In addition, Patent Document 2 (JP 2020-116001 A) discloses an infusion monitoring device that includes a first control unit that controls the amount of light emitted by each of a plurality of light-emitting elements to improve the function of detecting droplets falling inside the infusion tube, and a second control unit that causes the first control unit to control the amount of light emitted by each light-emitting element based on the amount of light received by the light-receiving element when droplets are not passing through the inside of the infusion tube. This makes it possible to align the amount of light received by the light-receiving element to a predetermined value even if the characteristics of each light-emitting element vary.

[0004] JP 2014-204897 A JP 2020-116001 A

[0005] The inventors have discovered that depending on the liquid used in the drip tube, fogging may occur inside and outside the drip tube, adversely affecting the accuracy of droplet monitoring. For example, when administering infusion to a human body, the infusion may be heated to prevent a drop in body temperature. This can lead to fogging inside and outside the drip tube due to the temperature difference between the inside of the drip tube and the outside air surrounding the drip tube. Furthermore, when measuring liquids excreted from the human body (e.g., urine), the temperature difference between the inside of the drip tube and the outside air surrounding the drip tube can cause fogging inside and outside the drip tube because the liquid excreted from the body is close to body temperature.

[0006] Therefore, the object of the present invention is to provide a drip monitoring sensor that can be attached to a drip tube and monitors droplets falling inside the drip tube, and that can suppress deterioration of droplet monitoring accuracy due to fogging that occurs inside and outside the drip tube.

[0007] The above object is achieved by the following: A drip monitoring sensor that can be attached to a drip tube and monitors droplets falling inside the drip tube, the drip monitoring sensor comprising a droplet detection unit for detecting the droplets falling inside the drip tube, the droplet detection unit comprising a droplet detection light-emitting unit that irradiates first detection light, and a droplet detection light-receiving unit that can receive the first detection light irradiated by the droplet detection light-emitting unit and outputs a first light-receiving signal corresponding to the received first detection light, and the optical axis of the first detection light that linearly connects the droplet detection light-emitting unit and the droplet detection light-receiving unit intersects with the drop path of the droplet, Furthermore, the drip monitoring sensor is provided with a drip tube fogging detection unit that includes a fogging detection light-emitting unit that irradiates second detection light, and a fogging detection light-receiving unit that can receive the second detection light irradiated by the fogging detection light-emitting unit and output a second light-receiving signal corresponding to the received second detection light. The drip monitoring sensor is configured so that the optical axis of the second detection light that linearly connects the fogging detection light-emitting unit and the fogging detection light-receiving unit does not intersect with the drop path of the droplets and the optical axis of the first detection light.

[0008] FIG. 1 is a front view showing an embodiment of the drip monitoring sensor of the present invention attached to a drip tube. FIG. 2 is a cross-sectional view taken along the line A-A in FIG. 1. FIG. 3 is a block diagram illustrating the configuration of the drip monitoring sensor shown in FIG. 1. FIG. 4 is a front view schematically illustrating a portion of a urinary oxygen monitoring system including the drip monitoring sensor shown in FIG. 1. FIG. 5 is a front view showing an example of a drip tube to which the drip monitoring sensor shown in FIG. 1 is attached. FIG. 6 is an explanatory diagram illustrating changes in the amount of light received by the droplet detection light-receiving unit of the drip monitoring sensor shown in FIG. 1. FIG. 7 is an explanatory diagram illustrating changes in the amount of light received by the droplet detection light-receiving unit of the drip monitoring sensor shown in FIG. 1. FIG. 8 is a flow chart illustrating an embodiment of the control flow for drip monitoring using the drip monitoring sensor shown in FIG. 1. FIG. 9 is a flow chart illustrating another embodiment of the control flow for drip monitoring using the drip monitoring sensor shown in FIG. 1. FIG. 10 is a flow chart illustrating a portion of the control flow shown in FIG. 8. FIG. 11 is a flow chart illustrating another embodiment of the control flow for drip monitoring using the drip monitoring sensor shown in FIG. 1. Fig. 12 is a flow chart for explaining another embodiment of the control flow for drip monitoring using the drip monitoring sensor shown in Fig. 1. Fig. 13 is a cross-sectional view showing another embodiment of the drip monitoring sensor of the present invention attached to a drip tube. Fig. 14 is a front view showing another embodiment of the drip monitoring sensor of the present invention attached to a drip tube. Fig. 15 is a front view showing the state when the drip monitoring sensor is attached to or detached from the drip tube in the embodiment shown in Fig. 14.

[0009] The drip monitoring sensor of the present invention will be described using an embodiment shown in the drawings. As shown in Figures 1 to 3, the drip monitoring sensor 1 of the present invention is a drip monitoring sensor 1 that can be attached to a drip tube 50 and monitors droplets 60 falling inside the drip tube 50. It includes a droplet detection unit 10 for detecting droplets 60 falling inside the drip tube 50. The droplet detection unit 10 includes a droplet detection light-emitting unit 11 that emits first detection light, and a droplet detection light-receiving unit 12 that can receive the first detection light emitted by the droplet detection light-emitting unit 11 and output a first light-receiving signal corresponding to the received first detection light. The optical axis P1 of the first detection light, which linearly connects the droplet detection light-emitting unit 11 and the droplet detection light-receiving unit 12, intersects with the droplet fall path F. In this embodiment, the droplet fall path F is a path along which droplets 60 fall from the tip (lower end) of the dripping portion 52 described later above the liquid level of the stored liquid 55 described later. Furthermore, the drip monitoring sensor 1 includes a fogging detection light-emitting unit 21 that emits second detection light, and a fogging detection light-receiving unit 22 that can receive the second detection light emitted by the fogging detection light-emitting unit 21 and output a second light-receiving signal corresponding to the received second detection light. The drip tube includes a fogging detection unit 20, and the optical axis P2 of the second detection light linearly connecting the fogging detection light-emitting unit 21 and the fogging detection light-receiving unit 22 does not intersect with the droplet fall path F and the optical axis P1 of the first detection light.

[0010] The control unit 70, memory unit 71, notification unit 72, and display unit 73 shown in FIG. 3 (block diagram) which are provided in the infusion monitoring sensor 1 of this embodiment are not shown in FIGS. 1 and 2, but for example, the control unit 70, memory unit 71, notification unit 72, and display unit 73 may each be provided in the infusion monitoring sensor 1 (infusion tube covering unit 30, etc.) shown in FIGS. 1 and 2, or may be provided as separate components electrically connected to such infusion monitoring sensor 1.

[0011] The drip monitoring sensor 1 of this embodiment can be used as a drip monitoring sensor for urine or infusion. In this embodiment, an example in which the drip monitoring sensor 1 is used as a drip monitoring sensor for urine will be described.

[0012] A urinary oxygen monitoring system 100 in which the infusion monitoring sensor 1 of this embodiment can be used is outlined in Figure 4. The urinary oxygen monitoring system 100 includes a urinary catheter (not shown), urine drainage tubes 102 and 103 (upstream tube 102 and downstream tube 103 sandwiching a drip tube 50) for guiding urine from the urinary catheter to a urine bag 101, the urine bag 101 for storing urine, and a system main body (console) 104. Although not shown, various sensors (oxygen partial pressure (oxygen concentration) sensor, temperature sensor, flow rate sensor, conductivity sensor, etc.) are provided in the urinary catheter and urine drainage tubes 102 and 103, allowing various data (urinary oxygen partial pressure (oxygen concentration), temperature, urine flow rate, conductivity, etc.) to be measured.

[0013] The system main body 104 includes various means for controlling the devices included in the entire system (such as various sensors), calculating measured data, and displaying the measured data. The system main body 104 may cooperate with the infusion monitoring sensor 1 (including the control unit 70, memory unit 71, notification unit 72, and display unit 73 of the infusion monitoring sensor 1, which will be described later). In this case, the system main body 104 may include, for example, a display capable of displaying the measured data as the display unit 73, a light-emitting element for optically notifying the measured data or an abnormality in the infusion tube 50, or a speaker for audibly notifying the measured data or an abnormality in the infusion tube 50 as the notification unit 72.

[0014] The drip monitoring sensor 1 of this embodiment is attached to a drip tube 50 provided midway through the urinary drainage tubes 102, 103, and can be used to monitor droplets (urine) 60 falling inside the drip tube 50 and measure the flow rate of urine. In this embodiment, the drip monitoring sensor 1 is provided separately from the system main body 104 and is connected to the system main body 104. The system main body 104 may have the drip monitoring sensor of the present invention built in.

[0015] As shown in FIG. 5 , the drip tube 50 includes a drip section 52 that introduces liquid (urine) from the upstream tube 102 into the drip chamber 51 therein, a discharge section 53 that discharges the liquid (urine) in the drip chamber 51 into the downstream tube 103, and a peripheral wall section 54 that defines the peripheral surface of the drip chamber 51. The peripheral wall section 54 is formed of a light-transmitting material, allowing the interior of the drip chamber 51 to be viewed from the outside. A portion of the peripheral wall section 54 may be light-impermeable. The peripheral wall section 54 preferably includes a light-transmitting section at least above the liquid level of the stored liquid 55, which will be described later. An outwardly protruding flange section 56 is provided on the upper portion of the peripheral wall section 54.

[0016] Liquid introduced into drip tube 50 from urine drainage tube (upstream tube) 102 falls as droplets 60 from drip section 52 and is temporarily stored in drip chamber 51 (reserved liquid 55). Discharge section 53 discharges a portion of retained liquid 55 into urine drainage tube (downstream tube) 103 to maintain an appropriate amount of retained liquid 55 in drip chamber 51.

[0017] As shown in FIG. 1, the drip monitoring sensor 1 of this embodiment includes a drip tube covering portion 30 that covers the drip tube 50 over a predetermined length in the direction of droplet 60 fall (the vertical direction in FIG. 1). Specifically, the drip tube covering portion 30 of this embodiment includes a first covering member 31 and a second covering member 32, each having an inner shape corresponding to the drip tube 50, and covers the entire length of the drip tube 50 in the vertical direction. The drip tube covering portion may cover a portion of the drip tube in the vertical direction, including the droplet fall path F (the portion from the bottom of the drip portion 52 to the top surface of the stored liquid 55).

[0018] The first covering member 31 and the second covering member 32 are connected to each other via a hinge portion 33 at one side (the upper side in FIG. 2) so that they can be rotated (opened and closed), and the other side (the lower side in FIG. 2) is fastened with a stopper portion 34, thereby being attached (fixed) to the drip tube 50. The inside of the drip tube covering portion 30 (the first covering member 31 and the second covering member 32) has a shape (engagement recess 35) that engages with the flange portion 56 provided on the upper part of the peripheral wall portion 54 of the drip tube 50, so that the drip tube covering portion 30 does not detach (fall) from the drip tube 50.

[0019] In this embodiment, the drip tube covering portion 30 is made of a non-light-transmitting or light-slightly light-transmitting material. This prevents or prevents light from entering the drip monitoring sensor 1 (the droplet detection light-receiving portion 12 and the fogging detection light-receiving portion 22, which will be described later) even when the drip tube 50 and the drip monitoring sensor 1 are used in a hospital room or the like where an external light source (such as a fluorescent lamp or an incandescent lamp) is present.

[0020] In addition, as shown in FIGS. 1 and 2, the drip tube covering portion 30 of this embodiment is provided with a slit portion 36 (a gap provided between the first covering member 31 and the second covering member 32). The slit portion 36 is provided over the entire vertical length of the drip tube covering portion 30, and the drip tube 50 (inside the drip chamber 51) can be viewed from the slit portion 36. The slit portion may be provided in a portion of the drip tube covering portion in the vertical direction. In addition, a through hole may be provided in a portion of the drip tube covering portion, or a portion of the drip tube covering portion may be formed from a light-transmitting material, thereby providing a window portion in the drip tube covering portion for viewing the drip tube 50 (inside the drip chamber 51). In addition, the drip tube covering portion does not need to be provided with such a slit portion or window portion.

[0021] The drip tube covering part may have a pressing part that presses against the drip tube, and the drip tube covering part may be fixed to the drip tube by the pressing part. For example, although not shown, a biasing member (such as a spring) may be used to bias the first covering member and the second covering member in a direction toward each other, or an elastic member (such as rubber or elastomer) may be disposed inside the drip tube covering part, and the elastic force (resilience) of such an elastic member may be used to press against the drip tube, thereby fixing the drip tube covering part to the drip tube.

[0022] In this embodiment, as shown in FIG. 2, a droplet detection light-emitting unit 11, a droplet detection light-receiving unit 12, a fogging detection light-emitting unit 21, and a fogging detection light-receiving unit 22 are provided on the inner surface of the drip tube covering unit 30.

[0023] It is preferable that the droplet detection light-emitting unit 11 and the fogging detection light-emitting unit 21 are equipped with, for example, an LED or a semiconductor laser (laser diode), and that the amount of light emitted by each of them (first detection light and second detection light) can be adjusted by adjusting the power supplied.

[0024] Preferably, the droplet detection light-receiving unit 12 and the fogging detection light-receiving unit 22 each include, for example, a phototransistor or a photodiode, and are capable of outputting a signal (first light-receiving signal and second light-receiving signal) corresponding to the amount of light received (first detection light and second detection light). Such signals (first light-receiving signal and second light-receiving signal) may be electrical signals, such as a current signal, a voltage signal converted from the current signal, or a digital signal containing information corresponding to the amount of light.

[0025] The drip monitoring sensor 1 includes a droplet detection unit 10 including a droplet detection light-emitting unit 11 that emits a first detection light and a droplet detection light-receiving unit 12 that can receive the first detection light emitted by the droplet detection light-emitting unit 11 and output a first light-receiving signal corresponding to the received first detection light. As shown in FIG. 3, the droplet detection unit 10 may also include a droplet analysis unit 13 that performs droplet detection, flow rate calculation, free flow (flowing down) determination, no flow (no dripping) determination, etc., based on the first light-receiving signal. Furthermore, the processing performed by such a droplet analysis unit may be performed using external equipment (e.g., various means included in the system main body 104).

[0026] As shown in FIG. 2, the droplet detection unit 10 has an optical axis P1 of the first detection light, which linearly connects the droplet detection light-emitting unit 11 and the droplet detection light-receiving unit 12, intersecting with the droplet fall path F, allowing the droplets 60 falling inside the drip tube 50 to be detected. The droplet detection light-emitting unit 11 may be provided with a member (e.g., a lens) to prevent the first detection light from diffusing (to increase the directivity of the first detection light to the droplet detection light-receiving unit 12). This improves the detection accuracy of the droplets 60 and suppresses the adverse effects on the fogging detection of the drip tube 50, which will be described later. The droplet detection light-receiving unit 12 may also be provided with a member (e.g., a lens) to converge (focus) the received first detection light. This improves the detection accuracy of the droplets 60.

[0027] The principle of detecting droplets 60 falling inside the drip tube 50 in the droplet detection unit 10 will be briefly explained. The amount of first detection light received by the droplet detection light receiving unit 12 of the droplet detection unit 10 changes depending on whether or not the droplet 60 is passing inside the drip tube 50. Specifically, the first detection light emitted by the droplet detection light emitting unit 11 is attenuated when it is blocked by the droplet 60 (when the droplet 60 is present on the optical axis P1 of the first detection light). In other words, when the droplet 60 is passing inside the drip tube 50, the amount of first detection light received by the droplet detection light receiving unit 12 is reduced compared to when the droplet 60 is not passing inside the drip tube 50. The droplet detection light receiving unit 12 outputs a first light receiving signal based on the amount of light received. That is, the droplet detection unit 10 can detect droplets 60 falling inside the drip tube 50 based on changes in the first light receiving signal, which changes based on changes in the amount of light of the first detection light received by the droplet detection light receiving unit 12.

[0028] The drip monitoring sensor 1 includes a drip tube fogging detection unit 20, which includes a fogging detection light-emitting unit 21 that emits second detection light and a fogging detection light-receiving unit 22 that can receive the second detection light emitted by the fogging detection light-emitting unit 21 and output a second light-receiving signal corresponding to the received second detection light. As shown in FIG. 3, the fogging detection unit 20 may also include a fogging analysis unit 23 that performs fogging detection (determines the fogging level (degree of fogging) on ​​the inner or outer surface (inside and outside the drip tube) of the peripheral wall 54 of the drip tube 50) based on the second light-receiving signal. The processing performed by the fogging analysis unit may also be performed using external equipment (e.g., various means included in the system main body 104).

[0029] In the fogging detection unit 20, the optical axis P2 of the second detection light, which linearly connects the fogging detection light-emitting unit 21 and the fogging detection light-receiving unit 22, does not intersect with the droplet drop path F and the optical axis P1 of the first detection light. This reduces the influence of the droplets 60 and the first detection light on the fogging detection unit 20, improving the accuracy of fogging detection of the drip tube 50 in the fogging detection unit 20. On the other hand, the influence of the second detection light on the droplet detection unit 10 can also be reduced, improving the detection accuracy of the droplets 60 in the droplet detection unit 10.

[0030] In addition, a member (e.g., a lens, etc.) may be provided on the fogging detection light-emitting unit 21 to prevent the second detection light from diffusing (to increase the directivity of the second detection light to the fogging detection light-receiving unit 22). This improves the fogging detection accuracy of the drip tube 50 and suppresses the adverse effects on droplet detection described above. In addition, a member (e.g., a lens, etc.) for converging (condensing) the received second detection light may be provided on the fogging detection light-receiving unit 22. This improves the fogging detection accuracy of the drip tube 50.

[0031] The principle of detecting fogging in the drip tube 50 in the fogging detection unit 20 will be briefly explained. Note that, here, fogging in the drip tube 50 refers mainly to fogging inside and outside the drip tube 50 caused by a temperature difference between the inside and outside of the drip tube 50 (for example, the temperature difference that occurs when handling a liquid (for example, a heated infusion or urine) that is hotter than the ambient temperature), and refers to fine water droplets (condensation) adhering to the inner and / or outer surfaces of the drip tube 50 (peripheral wall portion 54), steam generated inside the drip tube 50, etc.

[0032] The amount of second detection light received by the fogging detection light receiving unit 22 of the fogging detection unit 20 varies depending on whether fogging occurs in the drip tube 50. Specifically, the second detection light emitted by the fogging detection light emitting unit 21 is attenuated when fogging occurs in the drip tube 50 (when fogging exists on the optical axis P2 of the second detection light). In other words, when fogging occurs in the drip tube 50, the amount of second detection light received by the fogging detection light receiving unit 22 is reduced compared to when fogging does not occur in the drip tube 50. The fogging detection light receiving unit 22 outputs a second light receiving signal based on the amount of received light. In other words, the fogging detection unit 20 can detect fogging in the drip tube 50 based on changes in the second light receiving signal, which changes based on changes in the amount of second detection light received by the fogging detection light receiving unit 22.

[0033] In the drip monitoring sensor 1 of this embodiment, as shown in FIG. 2, the fogging detection light-emitting unit 21 is positioned closer to the droplet detection light-receiving unit 12 than the droplet detection light-emitting unit 11, and the fogging detection light-receiving unit 22 is positioned closer to the droplet detection light-emitting unit 11 than the droplet detection light-receiving unit 12. In other words, for example, in FIG. 2, the center of the droplet fall path F is set as the origin, and an X-axis (extending along the optical axis P1 of the first detection light) is assumed in the direction in which the droplet detection light-emitting unit 11 and the droplet detection light-receiving unit 12 face each other. Furthermore, a Y-axis perpendicular to the X-axis is assumed. When the XY plane is assumed in FIG. 2, the fogging detection light-emitting unit 21 is positioned closer to the droplet detection light-receiving unit 12 than the droplet detection light-emitting unit 11 (positioned on the positive side of the X-axis), i.e., in the second or third quadrant (negative side of the X-axis). On the other hand, the fogging detection light-receiving unit 22 is located closer to the droplet detection light-emitting unit 11 than the droplet detection light-receiving unit 12 (located on the negative side of the X-axis), i.e., in the first or fourth quadrant (positive side of the X-axis). This prevents the second detection light emitted by the fogging detection light-emitting unit 21 from entering the droplet detection light-receiving unit 12, improving droplet detection accuracy. Also, it prevents the first detection light emitted by the droplet detection light-emitting unit 11 from entering the fogging detection light-receiving unit 22, improving fogging detection accuracy.

[0034] In addition, in this embodiment, as shown in FIG. 2, the distance between the fogging detection light-emitting element 21 and the fogging detection light-receiving element 22 (the distance in the left-right direction in FIG. 2) is shorter than the distance between the droplet detection light-emitting element 11 and the droplet detection light-receiving element 12.

[0035] In addition, in the drip monitoring sensor 1 of this embodiment, as shown in FIG. 1, the fogging detection light-emitting unit 21 and the fogging detection light-receiving unit 22 are arranged on the upper side of the drip tube 50 (upper side in the falling direction of the droplets 60) than the droplet detection light-emitting unit 11 and the droplet detection light-receiving unit 12. In other words, the optical axis P1 of the first detection light and the optical axis P2 of the second detection light are offset in the vertical direction, and the optical axis P2 of the second detection light is above the optical axis P1 of the first detection light. This suppresses the incidence of the second detection light irradiated by the fogging detection light-emitting unit 21 on the droplet detection light-receiving unit 12, thereby improving droplet detection accuracy. In addition, the incidence of the first detection light irradiated by the droplet detection light-emitting unit 11 on the fogging detection light-receiving unit 22 is suppressed, thereby improving fogging detection accuracy.

[0036] Furthermore, by arranging the fogging detection unit 20 on the upper side of the drip tube 50, fogging inside and outside the drip tube 50, which is likely to occur on the upper side of the drip tube 50 due to the temperature difference that occurs when handling liquids that are hotter than the outside air temperature (for example, heated infusions or urine, etc.), can be more reliably detected. Note that, if fogging inside and outside the drip tube 50 can be detected, the fogging detection light-emitting unit 21 and the fogging detection light-receiving unit 22 can be arranged on the lower side of the drip tube 50 (lower in the direction of droplet 60 falling) than the droplet detection light-emitting unit 11 and the droplet detection light-receiving unit 12, and the optical axis P2 of the second detection light can be located below the optical axis P1 of the first detection light.

[0037] In the drip monitoring sensor 1, the wavelength of the first detection light received by the droplet detection light-receiving unit 12 may be different from the wavelength of the second detection light received by the fogging detection light-receiving unit 22. For example, the wavelength of the first detection light emitted by the droplet detection light-emitting unit 11 may be different from the wavelength of the second detection light emitted by the fogging detection light-emitting unit 21. To achieve this, the droplet detection light-emitting unit 11 and the fogging detection light-emitting unit 21 may be different (e.g., different LEDs), or the droplet detection light-emitting unit 11 and the fogging detection light-emitting unit 21 may each be provided with an optical filter that transmits light of a different specific wavelength. Furthermore, the droplet detection light-receiving unit 12 and the fogging detection light-receiving unit 22 may be different (e.g., different photodiodes). In addition, the droplet detection light receiving unit 12 (or droplet analysis unit 13) and / or the fogging detection light receiving unit 22 (or fogging analysis unit 23) may be provided with an optical filter that passes light of a specific wavelength (or cuts off light of a specific wavelength), or an electrical (soft) filter that amplifies or cuts off electrical signals corresponding to light of a specific wavelength may be provided.

[0038] 3, the drip monitoring sensor 1 of this embodiment includes a control unit 70 that adjusts the amount of light emitted by the droplet detection light-emitting unit 11 based on the second light-receiving signal. In other words, the control unit 70 of the drip monitoring sensor 1 adjusts the amount of light emitted by the first detection light in accordance with the fogging (fogging level) of the drip tube 50 detected based on the second light-receiving signal.

[0039] When the drip tube 50 is cloudy, the first detection light emitted by the droplet detection light-emitting unit 11 is attenuated, which may deteriorate the detection accuracy of the droplet 60. For example, as shown in FIG. 7, when the drip tube 50 is cloudy, the difference (r3-r4) between the amount of light received by the droplet detection light-receiving unit 12 when the droplet 60 is not passing (the droplet 60 is not on the optical axis P1 of the first detection light) and the amount of light received by the droplet detection light-receiving unit 12 when the droplet is passing (the droplet 60 is on the optical axis P1 of the first detection light) is r3. When there is no fogging on the optical axis P1 of the first detection light, the difference (r1-r2) between the amount of light received by the droplet detection light-receiving unit 12 (the magnitude of the first light-receiving signal) r1 when no droplets 60 are passing (the droplets 60 are not on the optical axis P1 of the first detection light) and the amount of light received by the droplet detection light-receiving unit 12 (the magnitude of the first light-receiving signal) r2 when droplets are passing (the droplets 60 are on the optical axis P1 of the first detection light) is smaller than the difference (r1-r2) [(r3-r4)<(r1-r2)]. As a result, some or all of the droplets 60 that should be detected may not be detected, which could result in a deterioration in the detection accuracy of the droplets 60 or an erroneous detection of no flow (no dripping).

[0040] Furthermore, when the size of the droplet 60 is detected based on the transit time of the droplet 60 and used to measure the flow rate, fogging causes the amount of light received by the droplet detection light receiving unit 12 (the magnitude of the first light receiving signal) to change slowly, which can result in the transit time (t2-t1) from the beginning to the end of the droplet 60 that should be detected being falsely detected (t3-t4), which may result in a deterioration in the accuracy of the flow rate measurement based on droplet detection (the number of droplets per unit time and the size of the droplets).

[0041] In addition, if the amount of light received by the droplet detection light receiving unit 12 (the magnitude of the first light receiving signal) changes from r1 shown in FIG. 6 to r3 shown in FIG. 7 due to the sudden occurrence of fogging, the droplet detection unit 10 may mistakenly detect a state in which the liquid is rapidly flowing down the drip tube 50 without flow rate control (so-called free flow).

[0042] The drip monitoring sensor 1 of this embodiment adjusts the amount of light of the first detection light according to the cloudiness (cloudiness level) of the drip tube 50 detected based on the second light receiving signal (for example, by increasing the amount of light so that the waveform shown in Figure 7 approaches the waveform shown in Figure 6), thereby improving the accuracy of droplet detection.

[0043] The drip monitoring sensor 1 may also include a fogging suppression mechanism that suppresses fogging inside the drip tube 50 based on the second light receiving signal. Examples of such a fogging suppression mechanism that suppresses fogging inside the drip tube 50 based on the second light receiving signal include a heater and an ultrasonic vibrator. The operation of such a fogging suppression mechanism can be controlled by the above-mentioned control unit 70, etc.

[0044] The drip monitoring sensor 1 also includes a fogging suppression mechanism that suppresses fogging inside the drip tube 50. The fogging suppression mechanism may include a heater, a heat insulating section, a heat dissipation section, or an ultrasonic vibrator. Such a fogging suppression mechanism may be embedded in the drip tube covering section 30 (first covering member 31, second covering member 32), for example.

[0045] 3, the drip monitoring sensor 1 may further include a memory unit 71 that stores the value of the second detection light received by the fogging detection light receiving unit 22 when the control unit 70 maximizes the light output of the first detection light as a threshold value, and a notification unit 72 that notifies when the value of the second detection light received by the fogging detection light receiving unit 22 falls below the threshold value. This allows for rapid notification of the occurrence of fogging at a level that requires the maximum output of the first detection light, or the occurrence of fogging at a level that the droplet detection light receiving unit 12 cannot receive the first detection light output at maximum output. This prevents dripping from continuing when droplet detection accuracy cannot be ensured, and allows for early detection of unexpected abnormalities in the drip tube 50.

[0046] An example of a control flow for infusion monitoring using the infusion monitoring sensor 1 as described above will be briefly described with reference to FIGS. 8 to 12. FIG.

[0047] In this embodiment, after the start of drip monitoring (START), first, fogging detection is performed by the fogging detection unit 20 (step S1). Here, the fogging level is detected based on the second light receiving signal by the fogging analysis unit 23. Thereafter, control proceeds to step S2.

[0048] In step S2, it is determined whether the cloudiness level detected in step S1 is equal to or lower than a predetermined value. Specifically, if the cloudiness level detected in step S1 is greater than the predetermined value, control proceeds to step S3, where the amount of light emitted by the droplet detection light-emitting unit 11 is adjusted (increased) to ensure droplet detection accuracy. On the other hand, if the cloudiness level detected in step S1 is equal to or lower than the predetermined value, it is determined that no cloudiness that would deteriorate droplet detection accuracy has occurred, and the adjustment of the light amount is canceled (reset) in step S4. After processing in step S3 or S4, control proceeds to step S5.

[0049] In step S5, droplet detection is performed to determine whether droplets have been detected normally. Specifically, it is determined whether droplets (changes in the amount of light received by the droplet detection light receiving unit 12 (magnitude of the first light receiving signal)) have been detected within a predetermined range. If it is determined in step S5 that droplet detection has not been performed normally, control proceeds to flow B, which will be described later. If it is determined in step S5 that droplet detection has been performed normally, control proceeds to step S6.

[0050] In step S6, the liquid flow rate is calculated using the droplet detection results. For example, the flow rate per unit time and the cumulative flow rate since the start of measurement (monitoring) can be calculated using a preset volume per droplet and the detected amount (number) of droplets. The calculated flow rate may be displayed on the display unit 73. Furthermore, when the flow rate reaches a preset amount or when an abnormality such as an excess or deficiency occurs, the alarm unit 72 may be configured to notify the user. The waveform of the first light-receiving signal detected by the droplet detection unit 10 can also be used to perform more accurate flow rate calculations. For example, the start and end of each droplet (the droplet's transit time) can be detected, the volume of each droplet 60 calculated, and the cumulative volume can be used to calculate the liquid flow rate. As shown in FIG. 9, in drip monitoring using the drip monitoring sensor 1, the flow rate calculation (step S6) may not be performed.

[0051] After step S6, the control proceeds to step S7, where it is determined whether or not monitoring of the infusion has been completed, and if monitoring has not been completed, the control returns to step S1.

[0052] In the control flow for drip monitoring in this embodiment, by repeatedly detecting fogging (step S1), determining the fogging level (step S2), and adjusting or canceling the light intensity (step S3 or S4) during drip monitoring, the light intensity of the first detection light can be adjusted to ensure droplet detection accuracy at all times.

[0053] In addition, in flow B, which is performed when it is determined that droplet detection is not successful in step S5, as shown in FIG. 10, first, in step SB1, it is determined whether the voltage value (second light receiving signal) continues to decrease. If the decrease in the second light receiving signal (voltage value) continues despite the adjustment of the light intensity of the first detection light according to the cloudiness level (step S3 or S4), control is transferred to step SB2, and it is determined that the liquid is free flowing (flowing down) in the drip tube 50. On the other hand, if it is determined in step SB1 that the decrease in the voltage value (second light receiving signal) is not continuing, control is transferred to step SB3.

[0054] In step SB3, it is determined whether the voltage value (second light receiving signal) fluctuates by a predetermined value or more. If the second light receiving signal (voltage value) does not fluctuate by a predetermined value or more despite the light intensity adjustment of the first detection light according to the fogging level (step S3 or S4), control is transferred to step SB4, and it is determined that there is no flow (no drip) in the drip tube 50. On the other hand, if it is determined in step SB3 that the voltage value (second light receiving signal) fluctuates by a predetermined value or more, control is returned to step S2.

[0055] If it is determined in steps SB2 and SB4 that there is an abnormality in the infusion (free flow or no flow), control proceeds to step SB5, where the abnormality is notified. In step SB5, the abnormality can be notified by the notifying unit 72 using light or sound, or by displaying the abnormality on the display unit 73.

[0056] As shown in FIG. 11, in the control flow of drip monitoring using the drip monitoring sensor 1 of this embodiment, control regarding the operation and stop of the fogging suppression mechanism can also be performed. That is, if fogging of the drip tube 50 is detected (NO in step S2), the light intensity adjustment (step S3) is performed, and control may be shifted to step S3a, and the fogging suppression mechanism may be activated. On the other hand, if the fogging of the drip tube 50 is eliminated over time or by the operation of the fogging suppression mechanism (YES in step S2), the light intensity adjustment is released (reset) (step S4), and control may be shifted to step S4a, and the fogging suppression mechanism may be stopped.

[0057] 12, in the control flow of drip monitoring using the drip monitoring sensor 1 of this embodiment, as described above, if the cloudiness level is detected at a level exceeding a predetermined threshold, control can be performed to quickly notify. Specifically, between steps S1 and S2, step S2a is provided to determine whether the cloudiness level is below a threshold, and if the cloudiness level exceeds the threshold (i.e., if the droplet detection accuracy cannot be ensured or if there is a concern that an unexpected abnormality may occur in the drip tube 50), control is shifted to step S2b, and such a situation is quickly notified.

[0058] In addition, the configuration of the drip monitoring sensor is not limited to the above. For example, as shown in FIG. 13, the drip detection light-emitting unit 11a, the drip detection light-receiving unit 12, the fogging detection light-emitting unit 21a, and the fogging detection light-receiving unit 22 may be arranged in the same plane (without vertical offset) perpendicular to the falling direction of the droplets 60, as in the drip monitoring sensor 1a. In addition, in this embodiment, the drip detection light-emitting unit 11a and the fogging detection light-emitting unit 21a are configured using the same light-emitting unit (e.g., LED). Even in this configuration, the optical axis P2a of the second detection light, which linearly connects the fogging detection light-emitting unit 21a and the fogging detection light-receiving unit 22, does not intersect with the droplet fall path F and the optical axis P1a of the first detection light (within the drip tube 50). In such a case, it is preferable that the light-emitting units (droplet detection light-emitting unit 11a, fogging detection light-emitting unit 21a) emit detection light (first detection light, second detection light) containing light of multiple wavelengths, and that the wavelength of the light (first detection light) received by the droplet detection light-receiving unit 12 is different from the wavelength of the light (second detection light) received by the fogging detection light-receiving unit 22.

[0059] Although not shown, a single light-emitting element (light-emitting element for droplet detection, light-emitting element for fogging detection) may be provided with multiple light-receiving elements (light-receiving element for droplet detection, light-receiving element for fogging detection).

[0060] 14 and 15, the first covering member 31b and the second covering member 32b of the drip tube covering part 30b can be slidably mounted on the drip tube 50 by providing a biasing member 74 (such as a spring) that biases the two members relative to each other (so-called clamp type). In addition, in the drip monitoring sensor 1b of this embodiment, the drip tube covering part 30b is provided so as to cover only the upper part of the drip tube 50 (the part above the liquid level of the stored liquid 55).

[0061] The drip monitoring sensor of the present invention comprises a droplet detection unit for detecting droplets falling inside the drip tube, and the droplet detection unit comprises a droplet detection light-emitting unit that irradiates first detection light, and a droplet detection light-receiving unit that is capable of receiving the first detection light irradiated by the droplet detection light-emitting unit and outputs a first light-receiving signal corresponding to the received first detection light, and the optical axis of the first detection light that linearly connects the droplet detection light-emitting unit and the droplet detection light-receiving unit intersects with the droplet fall path. Furthermore, the drip monitoring sensor includes a drip tube fogging detection unit that includes a fogging detection light-emitting unit that emits second detection light and a fogging detection light-receiving unit that can receive the second detection light emitted by the fogging detection light-emitting unit and output a second light-receiving signal corresponding to the received second detection light. The optical axis of the second detection light, which linearly connects the fogging detection light-emitting unit and the fogging detection light-receiving unit, does not intersect with the droplet drop path and the optical axis of the first detection light. This reduces the impact of droplets and the first detection light on the fogging detection unit, improving the accuracy of fogging detection in the drip tube. Meanwhile, the impact of the second detection light on the droplet detection unit can also be reduced, improving the accuracy of droplet detection in the droplet detection unit.

[0062] The drip monitoring sensor of the present invention is as follows: (1) A drip monitoring sensor that can be attached to a drip tube and monitors droplets falling inside the drip tube, the drip monitoring sensor comprising a droplet detection unit for detecting the droplets falling inside the drip tube, the droplet detection unit comprising a droplet detection light-emitting unit that irradiates first detection light, and a droplet detection light-receiving unit that can receive the first detection light irradiated by the droplet detection light-emitting unit and outputs a first light-receiving signal corresponding to the received first detection light, and the optical axis of the first detection light that linearly connects the droplet detection light-emitting unit and the droplet detection light-receiving unit intersects with the falling path of the droplet, Furthermore, the drip monitoring sensor is provided with a drip tube fogging detection unit that includes a fogging detection light-emitting unit that irradiates second detection light, and a fogging detection light-receiving unit that can receive the second detection light irradiated by the fogging detection light-emitting unit and output a second light-receiving signal corresponding to the received second detection light. The drip monitoring sensor is configured so that the optical axis of the second detection light that linearly connects the fogging detection light-emitting unit and the fogging detection light-receiving unit does not intersect with the drop path of the droplets and the optical axis of the first detection light.

[0063] This drip monitoring sensor includes a droplet detection unit for detecting droplets falling inside the drip tube. The droplet detection unit includes a droplet detection light-emitting unit that irradiates first detection light, and a droplet detection light-receiving unit that is capable of receiving the first detection light irradiated by the droplet detection light-emitting unit and outputs a first light-receiving signal corresponding to the received first detection light. The optical axis of the first detection light, which linearly connects the droplet detection light-emitting unit and the droplet detection light-receiving unit, intersects with the droplet fall path. Furthermore, the drip monitoring sensor includes a drip tube fogging detection unit that includes a fogging detection light-emitting unit that emits second detection light and a fogging detection light-receiving unit that can receive the second detection light emitted by the fogging detection light-emitting unit and output a second light-receiving signal corresponding to the received second detection light. The optical axis of the second detection light, which linearly connects the fogging detection light-emitting unit and the fogging detection light-receiving unit, does not intersect with the droplet drop path and the optical axis of the first detection light. This reduces the impact of droplets and the first detection light on the fogging detection unit, improving the accuracy of fogging detection in the drip tube. Meanwhile, the impact of the second detection light on the droplet detection unit can also be reduced, improving the accuracy of droplet detection in the droplet detection unit.

[0064] The drip monitoring sensor may also be implemented as follows. (2) In the drip monitoring sensor described in (1) above, the drip monitoring sensor preferably includes a control unit that adjusts the amount of light emitted by the droplet detection light-emitting unit based on the second light-receiving signal. (3) In the drip monitoring sensor described in (1) or (2) above, the fogging detection light-emitting unit is preferably positioned closer to the droplet detection light-receiving unit than the droplet detection light-emitting unit, and the fogging detection light-receiving unit is preferably positioned closer to the droplet detection light-emitting unit than the droplet detection light-receiving unit. (4) In the drip monitoring sensor described in any of (1) to (3) above, the fogging detection light-emitting unit and the fogging detection light-receiving unit are preferably positioned closer to the upper side of the drip tube than the droplet detection light-emitting unit and the droplet detection light-receiving unit. (5) In the drip monitoring sensor described in any one of (1) to (4) above, it is preferable that the wavelength of the first detection light received by the droplet detection light receiving unit is different from the wavelength of the second detection light received by the fogging detection light receiving unit. (6) In the drip monitoring sensor described in any one of (1) to (5) above, it is preferable that a fogging suppression mechanism be provided that suppresses fogging inside the drip tube based on the second light receiving signal. (7) In the drip monitoring sensor described in any one of (1) to (6) above, it is preferable that the drip monitoring sensor be provided with a fogging suppression mechanism that suppresses fogging inside the drip tube, and the fogging suppression mechanism be provided with a heater, a heat insulating unit, a heat dissipation unit, or an ultrasonic vibrator. (8) In the drip monitoring sensor described in any one of (1) to (7) above, the drip monitoring sensor preferably includes a drip tube covering part that covers the drip tube over a predetermined length in the direction of droplet fall, and the droplet detection light-emitting part, the droplet detection light-receiving part, the fogging detection light-emitting part, and the fogging detection light-receiving part are preferably provided on the inner surface of the drip tube covering part. (9) In the drip monitoring sensor described in (8) above, the drip tube covering part preferably has a pressing part that presses against the drip tube, and the drip tube covering part is preferably fixed to the drip tube by the pressing part.(10) In the drip monitoring sensor described in any one of (1) to (9) above, the drip monitoring sensor is preferably a drip monitoring sensor for urine or infusion. (11) In the drip monitoring sensor described in (2) above, the drip monitoring sensor preferably further includes a storage unit that stores, as a threshold value, a value of the second detection light received by the fogging detection light-receiving unit when the control unit sets the light amount of the first detection light to a maximum output, and an alarm unit that issues an alarm when the value of the second detection light received by the fogging detection light-receiving unit falls below the threshold value.

Claims

1. A drip monitoring sensor that can be attached to a drip tube and monitors droplets falling inside the drip tube, wherein the drip monitoring sensor comprises a droplet detection unit for detecting the droplets falling inside the drip tube, the droplet detection unit comprises a droplet detection light-emitting unit that irradiates first detection light, and a droplet detection light-receiving unit that can receive the first detection light irradiated by the droplet detection light-emitting unit and outputs a first light-receiving signal corresponding to the received first detection light, and the optical axis of the first detection light that linearly connects the droplet detection light-emitting unit and the droplet detection light-receiving unit intersects with the drop path of the droplet, Furthermore, the drip monitoring sensor includes a fogging detection unit for the drip tube, which is equipped with a fogging detection light-emitting unit that emits second detection light, and a fogging detection light-receiving unit that can receive the second detection light irradiated by the fogging detection light-emitting unit and output a second light-receiving signal corresponding to the received second detection light. The drip monitoring sensor is characterized in that the optical axis of the second detection light, which linearly connects the fogging detection light-emitting unit and the fogging detection light-receiving unit, does not intersect with the drop path of the droplets and the optical axis of the first detection light.

2. The drip monitoring sensor according to claim 1, further comprising a control unit that adjusts the amount of light emitted by the droplet detection light-emitting unit for first detection based on the second light-receiving signal.

3. A drip monitoring sensor as described in claim 1 or 2, wherein the fogging detection light-emitting element is positioned closer to the droplet detection light-receiving element than the droplet detection light-emitting element, and the fogging detection light-receiving element is positioned closer to the droplet detection light-emitting element than the droplet detection light-receiving element.

4. A drip monitoring sensor as described in claim 1 or 2, wherein the light-emitting element for fogging detection and the light-receiving element for fogging detection are arranged on the upper side of the drip tube than the light-emitting element for droplet detection and the light-receiving element for droplet detection.

5. A drip monitoring sensor as described in claim 1 or 2, wherein the wavelength of the first detection light received by the droplet detection light receiving unit is different from the wavelength of the second detection light received by the fogging detection light receiving unit.

6. A drip monitoring sensor as described in claim 1 or 2, which is provided with a fogging suppression mechanism that suppresses fogging inside the drip tube based on the second light receiving signal.

7. The drip monitoring sensor according to claim 1 or 2, wherein the drip monitoring sensor is provided with a fogging suppression mechanism that suppresses fogging inside the drip tube, and the fogging suppression mechanism is provided with a heater, an insulating part, a heat dissipation part or an ultrasonic vibrator.

8. The drip monitoring sensor according to claim 1 or 2, further comprising a drip tube covering part that covers the drip tube over a predetermined length in the direction of droplet fall, and the droplet detection light-emitting part, the droplet detection light-receiving part, the fogging detection light-emitting part, and the fogging detection light-receiving part are provided on the inner surface of the drip tube covering part.

9. The drip monitoring sensor according to claim 8, wherein the drip tube covering portion has a pressing portion that presses against the drip tube, and the drip tube covering portion is fixed to the drip tube by the pressing portion.

10. The drip monitoring sensor according to claim 1 or 2, wherein the drip monitoring sensor is a drip monitoring sensor for urine or infusion.

11. The drip monitoring sensor according to claim 2, further comprising: a memory unit that stores, as a threshold value, the value of the second detection light received by the fogging detection light receiving unit when the control unit sets the light intensity of the first detection light to the maximum output; and an alarm unit that issues an alarm when the value of the second detection light received by the fogging detection light receiving unit falls below the threshold value.

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