JP3521989B2 - Infusion device and infusion pump having the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drip device and an infusion pump equipped with the drip device, and detects the volume of a drop that drops in a drip tube to obtain an actual liquid delivery amount per unit time, which is set in advance. The present invention relates to a technique of controlling a pump unit in comparison with a liquid delivery amount to improve infusion accuracy.

[0002]

2. Description of the Related Art Conventionally, in a drip device provided in an infusion pump or the like, in order to monitor the actual amount of liquid to be delivered, it is considered to obtain the volume of each liquid drop falling in the infusion tube of the infusion set. Came. For example, in Japanese Unexamined Patent Publication No. 5-317422, the diameter of a droplet is detected by measuring the transit time of the droplet passing between optical energy beams provided at different heights of the drip tube, and It is disclosed to calculate the volume of a droplet assuming a sphere with a diameter. In Japanese Laid-Open Patent Publication No. 3-231681, the irradiation time from one point is blocked and the time taken for the droplet to pass is measured, and the shape of the droplet is obtained by rotating a half wave portion of a sine curve around a reference line. It is disclosed that the volume of the droplet is calculated on the assumption that the rotating body has a spherical shape. The volume of these droplets is assumed to be a droplet shape in the falling direction (the former is a circle and the latter is a sine curve).

Further, W093 / 09407 discloses that the shape of a droplet is detected by a two-dimensional image and the volume of the droplet is calculated. US Patent 4,93
In JP-A-6,828, the width of a droplet is detected at predetermined time (scan time) intervals, and the portion (slice-shaped cylinder) having the detected width of the droplet has the same thickness (height). It is disclosed that the volume of the droplet is calculated by assuming that the droplet is overlapped with such a cylinder.

[0004]

However, when calculating the volume of a liquid drop assuming the liquid drop shape in the downward direction, the accurate value is not obtained because the liquid drop shape is not based on actual measurement. is not. When calculating the volume of a droplet in a two-dimensional image image, image processing such as extracting the contour of the droplet becomes complicated.

Further, assuming that all the portions (cylinders) having the detected width of the droplet have the same height, the volume of the droplet is calculated by stacking the cylinders of the same height. When calculating (by the piecewise quadrature method), it is easier to calculate the droplet volume than in the case of a two-dimensional image, but when it is necessary to calculate the droplet volume with high accuracy, Since the moving distance under the free fall at the detection position of each of the detected width portions is not taken into consideration, that is, it is assumed that the thickness (height) of each cylinder is the same, Is insufficient.

According to the present invention, the volume of a droplet can be highly accurately determined by the piecewise quadrature method by taking into consideration the movement distance of each portion having the detected width of the droplet on the basis of the free fall at the detection position. It is an object to provide a drip device for calculating and an infusion pump including the drip device.

[0007]

In order to achieve the above object, an infusion device of the present invention and an infusion pump equipped with the same have the following constitution. That is, based on a change in the amount of light received by the light emitting means that emits light toward the liquid droplets that drop in the drip tube, the light receiving means that receives the light emitted from the light emitting means to the liquid droplets, and the amount of light received by the light receiving means. A width detection means for detecting the width of the droplet at a predetermined position of the drip tube at a predetermined time interval, and a portion of the width of the droplet detected by the width detection means, the predetermined portion within the predetermined time. The volume of the droplet is calculated by using a distance calculation unit that calculates a distance moved at a position and a distance calculated by the distance calculation unit that corresponds to the width detected by the width detection unit at the predetermined time interval. And a volume calculating means for calculating.

[0008]

In the above structure, the light emitting means emits light toward the liquid droplets falling in the drip tube, and the light receiving means receives the light emitted from the light emitting means to the liquid droplets, and the width detecting means is provided. Based on a change in the amount of light received by the light receiving means, the width of the droplet at a predetermined position of the drip tube is detected at predetermined time intervals, and the distance calculating means is detected by the width detecting means of the liquid droplet. The width calculation means calculates a distance moved at the predetermined position within the predetermined time, and the volume calculation means corresponds to the width detected by the width detection means at the predetermined time interval. The volume of the droplet is calculated by using the distance calculated in step.

[0009]

Embodiments First, an outline of the drip device of the present embodiment and an infusion pump including the same will be summarized, and then a detailed description will be given. The drip device and the infusion pump including the drip device of the present embodiment are attached to an infusion tube following the infusion bag or the like to detect a falling liquid drop, and a drug (medicine solution) to the human body or the like.
To monitor the liquid transfer.

Therefore, the drip device and the infusion pump equipped with the drip device of the present embodiment irradiate light onto the droplets in order to accurately measure the volume of the falling infusion (droplet or drug). It has a light-receiving unit facing the light-emitting unit and receiving light. The feature of the present embodiment is that the change in the amount of received light received at a predetermined sampling interval (predetermined time interval) is extracted to detect the width (width) of the drop (droplet) and to detect the drop. Obtaining the distance (moving distance) at which each of the width parts falls at the detection position (predetermined position) during the predetermined sampling interval based on free fall, and calculating (calculating) the volume using the piecewise quadrature method. It is in.

With the above configuration, it is possible to calculate the volume of the liquid drop falling in the drip cylinder with high accuracy. The infusion pump equipped with the drip device of the present invention enables highly accurate and stable infusion injection with little variation in the flow rate of the solution. Hereinafter, an infusion device according to an embodiment of the present invention and an infusion pump including the same will be specifically described with reference to the drawings.

FIG. 1 shows a configuration example of an infusion device according to the present invention and an infusion pump including the same. With reference to FIG. 1, a flexible tube 1 following an infusion bag or the like is connected to a drip tube 2. Then, the infusion solution (medicine solution or medicine) in the tube 1 is sent downward because the tube 1 is sequentially squeezed downward by the tube pressing portion 8 of the infusion pump, and finally the infusion solution is delivered to the patient to which the tube 1 is connected. send.

In the drip tube 2, a light emitting portion 3 and a light receiving portion 4 are arranged so as to face each other. Substantially parallel near-infrared light 24 is emitted from the light emitting unit 3 toward the drip tube. The parallel light reaches the light receiving unit 4 while being attenuated by the outer wall of the drip cylinder and the drops (droplets). The amount of light that reaches the light receiving unit 4 undergoes a change that correlates with the size of the drop that is blocked. The light receiving unit 4 sends a light detection signal proportional to the received light amount to the calculation unit 5 and the light emission amount control unit 9.

The arithmetic unit 5 samples the light detection signal at predetermined time intervals and converts it into a digital signal. And
The change in the converted digital signal sequence (light detection signal) is detected, and the volume of the drop is calculated by the method described later. The obtained volume of one drop is integrated and converted into a liquid feed amount (liquid feed flow rate) per unit time. The pump control unit (flow rate control unit) 6 compares the calculated liquid feed amount (measured liquid feed amount) with a preset reference liquid feed amount to reduce the error between the motors 8 By controlling the rotation speed of
Controls the liquid transfer amount (liquid transfer flow rate).

The light emission amount control unit 9 extracts the direct current component of the light detection signal (the signal component when the drop does not pass), compares it with a predetermined reference level, and reduces the error of the other side. The light emission amount of 3 is controlled. Thereby, the calculation unit 5
Can detect a change in the light detection signal that depends only on the falling drops, without being affected by the material of the drip tube 2 and the change in the light amount due to fogging of the inner wall of the drip tube.

FIG. 9 shows a change in the amount of light due to the material of the above-mentioned drip barrel 2, the clouding of the inner wall of the drip barrel, and the correction (control) of the amount of light.
It is a figure explaining the example which does. 9, the horizontal axis represents the time axis and the vertical axis represents the amount of light received by the light receiving unit 4.
A curve CB shows the amount of received light (level) when the inner wall of the drip cylinder is not fogged. The curve CA indicates the amount of light received (level) when the inner wall of the drip cylinder is cloudy. As is clear from the figure, when the inner wall is fogged, the amount of received light (level) is lowered as a whole. Therefore, when the inner wall is fogged, the amount of light received when a drop has not passed is smaller than when it is not fogged (only d in the figure), and a predetermined threshold value for detecting the edge of the drop. Since the amount of received light Qth is approached, it is difficult to detect edges (start and end of drop detection). Further, when the amount of received light when the drop has not passed is less than the threshold amount of received light Qth, there is a possibility that the drop is erroneously detected even though the drop has not passed. On the other hand, by controlling the light emission amount of the light emitting unit 3 by the function of the light emission amount control unit 9 described above, the light reception amount (level) when the droplet does not pass is Q ₀ (the light reception amount when the inner wall is not fogged). Can be raised to At this time, the difference between the threshold light receiving amount Qth and the light receiving amount when the drop does not pass is sufficiently large, so that the edge of the drop can be stably detected. Further, it is possible to avoid erroneous detection of a drop.

FIG. 2 shows an example of the structure of the light emitting section 3. Referring to FIG. 2, the light emitting element drive circuit 10 is designed so that the light emitting element 11 can emit a stable light amount under the control of the light emission amount control unit 9. The light emitting element 11 is an LED that emits near infrared light. The light emitting element 11 may be a semiconductor laser.

The lens 12 produces parallel light. By using the parallel light, the change in the amount of received light is proportional to the area of the drop that blocks the light as viewed from the optical path direction. Then, as will be described later, the amount of change in the amount of light received through the slit can be made proportional to the width of the droplet, which facilitates the calculation of the volume of the droplet. A slit 131 is further placed on the light emitting surface. The slit 131 is used to obtain a light beam having a sufficiently narrow width (vertical length) with respect to the length of the drop in the falling direction.

FIG. 3 shows an example of the structure of the light receiving section. Referring to FIG. 3, slits 132 are provided on the light receiving surface. The slit 132 is used to prevent ambient light and to obtain a light beam having a sufficiently narrow width (length in the vertical direction) with respect to the length of the drop in the falling direction. The light beam that has passed through the slit 132 is condensed by the lens 14 and converted into an electric signal by the light receiving element 15 formed of a photodiode or a phototransistor. Then, it is amplified by the amplifier 16 and sent to the arithmetic unit 5 and the light emission amount control unit 9 as the light detection signal 17.

In FIGS. 2 and 3, the slits 131 and 132 can have a size of, for example, a vertical length of 0.5 mm to 1 mm and a horizontal length of 30 mm. The length of the slit in the vertical direction reduces the amount of light that is refracted and reflected from the portion (upper and lower portions) other than the portion of the droplet where the slit is located (in the vertical direction), and that light passes through the slit and reaches the light receiving surface. The smaller the better, so that it is never reached (ie, K can be O as described below). In addition, the length in the horizontal direction is set to have a size that covers the inner diameter of the drip tube, so that it is possible to detect all the drops that drop in the drip tube.

FIG. 4 shows an example of the configuration of the arithmetic unit 5. With reference to FIG. 4, the photodetection signal 17 passes through an anti-aliasing filter (low-pass filter) 18 and is converted into a digital signal by an A / D converter 19. The CPU unit including the CPU 20 and the memory 21 detects a change in the amount of received light due to a drop from the captured digital signal, calculates (calculates) the volume of the drop based on this, and integrates the calculated volume. Thus, the liquid supply amount (liquid supply flow rate) per unit time is obtained. The liquid transfer amount per unit time thus obtained is calculated by the external interface unit 22 through the pump control signal (flow rate control signal) 2
It is output as 3.

Next, a method for obtaining the volume of the dropped liquid will be described. Drops falling in the drip cylinder can be viewed as a rotating body with respect to a vertical (falling direction) axis. Then, as shown in the schematic view of FIG.
Letting the radius and thickness (height) of the circle of the m-th cylinder from the bottom be dm and Δlm, respectively, the volume V of the droplet can be calculated by the piecewise quadrature method, and Σπdm ² Δlm (Equation 1) Here, it is expressed as π: pi.

As shown in FIG. 6, the slit 1 of the light receiving section 4 is formed.
The size of 2 is defined as the length h in the vertical direction and the length w in the horizontal direction. The length h in the vertical direction is sufficiently shorter than the length w in the horizontal direction. The distance from the tip of the nozzle of the drip tube 2 to the center of the slit 13 is L. When the drip tube 2 is attached between the light emitting unit 3 and the light receiving unit 4 of the drip sensor, the light receiving amount Q ₀ of the light receiving unit 4 when the drop does not pass is that the light emitted from the light emitting unit 3 is parallel. Since it is light, it is proportional to the area of the slit, and Q ₀ = Awh (Equation 2) where A is the amount of light received per unit area.

FIG. 7 shows the change in the amount of light received when a drop drops pass through the slit. Attenuation (change) in the amount of received light due to drops at △ Q
Since the light emitted from the light emitting unit 3 is parallel light, the lateral width of the droplet and ΔQ have a constant correlation (proportional relationship). When approximating the volume of a drop as in (Equation 1), ΔQ when the m-th cylinder from the bottom of the drop (the radius of the circle is dm) passes in front of the slit is the drop transmittance K Assuming that the ratio of the amount of light passing through the drop and reaching the light receiving surface through the slit is ΔQ = A (1-K) (2dm) h (Equation 3). In fact, dm corresponds to the average radius in the slit of the portion corresponding to the m-th cylinder of the drop passing through the slit. Change in received light ΔQ is the width of the drop 2d
It is proportional to m, and dm = ΔQ / 2A (1-K) h (Equation 4). The dm in (Equation 1) can be obtained from (Equation 4). here. K can be set to 0 (or a value close to 0) when setting the distance between the drip tube and the light-receiving surface so that the light passing through the droplet and refracted and reflected does not reach the light-receiving surface. Calculation becomes easy.

Since the amount of light received A per unit area is affected by the state of the drip tube (clouding of the inner wall, etc.) and changes, a method of controlling the amount of light emitted from the light emitting section 3 to keep A constant,
That is, dm can be obtained more accurately by using the method of keeping Q ₀ constant (as described above). If the velocity at which the droplet leaves the nozzle tip of the drip tube is V ₀ ,
The distance L from the tip of the nozzle to the center of the slit, using the time t ₁ for the tail of the drop to pass through the center of the slit under free fall, is L = V ₀ · t ₁ + g · t ₁ ² Since it is expressed as / 2 (Equation 5), the time t ₁ is t ₁ = (− V ₀ + √ [V ₀ ² + 2gL]) / g (Equation 6) where g: gravity acceleration √ [x ]: Given by the root operation of x.

In the calculation unit 5, the sampling time interval (predetermined time interval) of the photodetection signal is set to Δt, and one drop is made between _n consecutive Δt (Δt ₁ to Δt _n ). Suppose you could sample. Let Δlm be the distance that a drop has fallen at the center of the slit during the _mth Δt _m (= Δt). That is, in (Equation 1), n cylinders forming a drop are formed at every sampling time interval Δt, and the height of each cylinder is a drop between Δt _m at the center of the slit. The fall distance (movement distance) of Referring to FIG.
The time t _{m-1 at} which the _m- th cylinder reaches the position of the center of the slit from the tip of the nozzle and the time t _{m at which} it separates are: t _m = t ₁ −Δt × (nm) (Equation 7) and t _{m − 1} = t ₁ −Δt × (n− (m−1)) (Equation 8)

As in (Equation 5), time t from the tip of the nozzle
_m, t the distance fallen in _m-1 after the droplet Ln-m, Ln chromatography (m-1) _{is, L nm = V 0 t m} + gt m 2/2 V 0 (t 1 - △ t × (n- _{m)) + g (t 1} - △ t × (n-m)) 2/2 ( equation 9) L _{n over (m-1) = V 0} t m + gt m-1 2/2 V 0 (t 1 - △ t × (n- (m- 1))) + g (t 1 - △ t × (n- (m-1))) is given by ^2/2 (equation 10). As shown in FIG. 10, L _nm and L _{n- (m-1)}
Is equal to the height Δlm of the mth cylinder,
△ l _{m is, △ l m = L nm -} L n- (m-1) = (V 0 + g · t 1) △ t-g (2 (nm) +1) △ t 2/2 ( Formula 11 ).

When the flow rate is low, it can be considered that the droplet is stationary at the tip of the nozzle, and V ₀ = 0 (Equation 12). Therefore, at this time (Equation 6), (Equation 1
1) is (from equation 12), △ l _{m is, △ l m = (√ [} 2gL]) △ t -g (2 (n-m) +1) △ t 2/2 ( equation 13). In this way, Δl _m in (Equation 1) is obtained.
Incidentally, in the conventional piecewise quadrature method, normally, without considering the movement distance based on the free fall for each part having the detected width of the drop, any part having the detected width of the drop, The speed of passing through the slit center is constant (√ [2g
h]), that is, approximated by the speed at which the tail of the drop passes through the center of the slit, the height of the cylinder is the value of the first term in (Equation 12) that is independent of m. That is, the heights of the cylinders are the same for all the cylinders and are inaccurate.

From the above, if the change ΔQ in the amount of received light due to a droplet is measured by sampling at a fixed time interval Δt, the radius dm and the height Δlm of the m-th cylinder can be calculated by (Equation 4) and (Equation 13), respectively. The volume of the drop can be obtained by finding and substituting it in (Equation 1). In the concrete calculation of the piecewise quadrature method, as shown in FIG. 10, the m-th cylinder is placed at a height of Δl _m below the measured lateral width of 2 dm (the liquid measured at the center of the slit has a width of 2 dm). Unlike the case where the drop portion is formed as having a moving distance during Δt before measurement, as shown in FIG. 11, Δ is above the measured lateral width 2 dm.
Height of 1 _m (distance of droplet width 2 dm measured at the center of slit, distance moved during Δt after measurement)
It is also possible to form it as one having But,
The difference in the volume of the liquid droplets obtained by these can be ignored by making Δt sufficiently small.
In (Equation 1), calculation can be performed in any case.

Further, in FIGS. 11 and 12, the front end and the rear end of the liquid droplet are just detected at the sampling time, but this can be established by making Δt sufficiently small. Can be considered Finally, the software flow in the arithmetic unit 5 will be described with reference to the flowchart of FIG.

In step S100, a drop number counter (eg, 8 drop counter) for counting a predetermined number of drops is set to 0.
Initialize to. Further, a predetermined number of drop volume integrated values (for example, 8 drop volume integrated values) for obtaining a predetermined number of drop volume integrated values are initially set to zero. Furthermore, a predetermined drop number detection timer (for example, an eight drop detection timer) that measures the time required to detect a predetermined number of drops (predetermined drop number detection time) is initialized to 0.

In step S1, the light detection signal from the light receiving section 4 is input at the sampling time interval Δt. In step S2, the input photodetection signal is filtered (filtering) to remove noise. In step S3, the change in the filtered light detection signal is checked. This check looks for the onset of changes due to drop drops. If it is not possible to confirm the beginning of the change in the droplet (that is, the droplet), the process returns to step S1 and the same processing is repeated. Further, if the start of the change of the drop is confirmed, the process proceeds to step S4, and the data of the light detection signal is stored in the memory 21 (FIG. 4).

In step S5, the change in the filtered light detection signal is checked again to see if the drop has fallen below the sensing range (ie, slit) of the light receiver 4 (ie, end of change due to drop). ) Confirm. If the end of the change cannot be confirmed, the process returns to step S1 and the same processing is repeated. If the end of the change is confirmed, the process proceeds to step S6.

In step S6, the drop number counter is incremented by 1, and the volume of the drop detected by the above-mentioned method is calculated (calculated) from the data stored in the memory 21. Further, the newly calculated drop volume is added to the previously calculated drop value. In step S7, it is checked by the drop number counter whether or not the accumulation of the volume of a predetermined drop (for example, 8 drops) has been completed. If not completed, the process returns to step S1. If finished, step S
Proceed to step 8 and calculate (calculate) the liquid delivery amount (liquid delivery flow rate) per unit time from the predetermined drop number detection time and the predetermined drop volume integrated value.
And compare it with the set standard liquid flow rate.

In step S9, a control signal based on the comparison in step S8 is sent to the pump control section, and step S1
Return to 00. By repeating the above steps, stable and highly accurate infusion can be performed. As described above, the infusion device of this embodiment and the infusion pump including the infusion device can suppress variations in the delivery amount of the infusion solution, and in particular, can be used for microinjection. Therefore, it is possible to reduce the labor and time required for handling the device in the medical field, and it is possible to take a lot of time for nursing a patient.

Further, the drip device and the infusion pump equipped with the drip device of the present embodiment determine the detected width of the liquid droplet at the detection position when the volume of the liquid droplet is obtained by the piecewise quadrature method as described above. Since the droplet volume was measured with high accuracy by considering the movement distance of each of the parts having the free fall, highly stable / highly accurate infusion can be performed regardless of what kind of chemical solution is used. Therefore, the infusion device of the present embodiment and the infusion pump including the same can be used anywhere in the medical field,
The usage range can be expanded.

In this embodiment, one set of light emitting / receiving elements was used to detect the drop and its width. However, a plurality of sets of this drop are arranged around the drip tube to drop from a plurality of angles. By detecting the width of the drop, the volume of the drop can be calculated even for a drop having a convex shape in which the shape viewed from the drop direction has a curvature other than a circle.

[0038]

As described above, according to the present invention, the light emitting means for emitting light toward the liquid droplets falling in the drip tube and the light receiving means for receiving the light emitted from the light emitting means to the liquid droplets. Means for detecting the width of the liquid droplet at a predetermined position (detection position) of the drip tube at predetermined time intervals (sampling time) based on a change in the amount of light received by the light receiving device; Distance calculating means for calculating the distance that the portion of the width of the liquid droplet detected by the width detecting means moves at a predetermined position of the battle machine within the predetermined time (distance that falls on the basis of free fall), and the predetermined time. And a volume calculation means for calculating the volume of the droplet (section quadrature method) using the widths detected by the width detection means at intervals of and the distances calculated by the corresponding distance calculation means. This allows the volume of the liquid droplets that drop through the drip cylinder to be accurately adjusted. In can be calculated.

Further, in the drip device as a preferred embodiment of the present invention, the light emitting means is provided with a light emitting amount control means for controlling the light emitting amount based on the light amount received by the light receiving means, so that the liquid droplet passes through. Since it is possible to adjust the amount of received light when not performing, the edge detection of the droplet is not erroneously detected due to a change in the amount of received light that is emitted due to fog on the inner wall of the drip cylinder, and the erroneous detection of the droplet itself is performed. It is possible to accurately detect a droplet and a width of the droplet and calculate the volume of the droplet with high accuracy.

Further, in the drip device as a preferred embodiment of the present invention, the slit and the lens are provided in the optical path of the light emitted from the light emitting means, thereby making it possible to irradiate the liquid droplets with parallel light. In addition, it is possible to prevent ambient light when receiving light and to obtain a light beam having a sufficiently narrow width with respect to the length in the drop direction of the droplet, so that the width of the droplet can be accurately detected at the position where the slit is present. Therefore, the volume of the liquid droplet can be calculated with high accuracy.

Further, in the drip device as a preferred embodiment of the present invention, the flow rate of the infusion solution passing through the drip tube is provided by providing the solution delivery flow rate calculating means for integrating the volumes of the dropped drops and calculating the solution delivery flow rate. It is possible to calculate with high accuracy. In a drip device as a preferred aspect of the present invention, a flow rate control means for controlling the liquid supply flow rate based on a comparison between the liquid supply flow rate calculated by the liquid supply flow rate calculation means and a predetermined reference liquid supply flow rate is provided. As a result, highly accurate flow rate control becomes possible.

Further, the infusion pump equipped with the above-mentioned drip device enables highly accurate and stable infusion of the infusion solution.

[Brief description of drawings]

FIG. 1 is a diagram showing an overall configuration of an infusion pump according to an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration example of a light emitting unit 3.

FIG. 3 is a diagram showing a configuration example of a light receiving unit 4.

FIG. 4 is a diagram showing a configuration example of a liquid feed amount calculation unit 5.

FIG. 5 is a diagram showing a calculation method for obtaining the volume of a droplet.

FIG. 6 is a positional relationship between the drip tube 2 and the slit of the light receiving section 4,
It is a figure which shows the size of a slit.

FIG. 7 is a diagram showing a change in the amount of received light due to a drop of droplets in the light receiving section 4.

FIG. 8 is a flowchart illustrating an example of processing performed by a liquid delivery amount calculation unit 5.

FIG. 9 is a diagram illustrating an example of processing performed by a light emission amount control unit 9.

FIG. 10 is a diagram illustrating the calculation of the height (thickness) of each cylinder by the piecewise quadrature method.

FIG. 11 is a diagram illustrating an example of forming each cylinder by the piecewise quadrature method.

[Explanation of symbols]

1 tube 2 drip tube 3 light emitting part 4 Light receiving part 5 Liquid transfer volume calculation unit 6 Pump control unit 7 motor 8 Tube pressing part 9 Light emission control unit 24 parallel light

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-4-51963 (JP, A) JP-A-3-231681 (JP, A) JP-A-5-317422 (JP, A) JP-A-5- 2025 (JP, A) JP 5-248899 (JP, A) JP 2-51022 (JP, A) JP 1-197613 (JP, A) JP 57-179712 (JP, A) US Pat. No. 4,936,828 (US, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) A61M 5/00 310 A61M 5/168 G01F 1/20

Claims (6)

(57) [Claims] 1. A light emitting means for irradiating light toward a liquid drop falling in a drip tube, a light receiving means for receiving light applied to the liquid drop from the light emitting means, and an amount of light received by the light receiving means. Based on the change, the width detecting means for detecting the width of the droplet at the predetermined position of the drip tube at a predetermined time interval, and the portion of the width of the droplet detected by the width detecting means are within the predetermined time. A distance calculating means for calculating the distance to move at the predetermined position, using the distance calculated by the distance calculating means corresponding to the width detected by the width detecting means at the predetermined time interval,
A drip device comprising: a volume calculation unit that calculates the volume of the droplet. 2. The drip device according to claim 1, wherein the light emitting unit further includes a light emission amount control unit that controls the light emission amount based on the light amount received by the light receiving unit. 3. The drip device according to claim 1, wherein the drip device is further provided with a slit and a lens in an optical path of the light emitted from the light emitting means. 4. The drip device further comprises a liquid sending flow rate calculating means for calculating a liquid sending flow rate by integrating the volumes of the dropped liquid drops. The drip device described. Wherein said infusion device further based on a comparison of the liquid feed flow rate and a predetermined reference liquid feed stream amount calculated by said feeding flow rate calculating means comprises a flow control means for controlling the liquid feed flow rate The infusion device according to claim 4, wherein 6. An infusion pump comprising the drip device according to any one of claims 1 to 5 .