JPH0534466A - Detecting device for drip - Google Patents

Abstract

PURPOSE:To enable droplets to be surely detected while promptly following changes by using as a reference value the amount of signals generated when no droplet passes through a drip tube, and causing a control portion to judge that a droplet passes through the tube when a change is caused by more than a certain value with respect to the reference value. CONSTITUTION:Light radiated from an LED 2 is allowed to pass through a lens 3 and illuminates a drip tube 4. Data from an image sensor 5 are sampled into a drip control portion 6 to determine whether a droplet is passing through the tube 4 or not according to the data. The droplet interval time proportional to the flow rate is compared with the droplet interval time detected so as to control a transfusion pump. The control portion 6 samples as a reference value the addition of amounts of signals generated when no droplet passes through the tube, and when a change is caused in the addition of signal amounts by more than a certain value from the reference value, judges that a droplet is passing through the tube; i.e., even when the liquid attaches to the inside of the drip tube 4, received images are compared with each other to detect the presence of drips, thus enabling detection of the drips without being affected by dimming of the drip tube 3 and by water droplets attaching thereto.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drip detecting device for detecting falling water drops.

[0002]

2. Description of the Related Art In the conventional drip detection, a light emitting diode and a photodiode (or a phototransistor) are combined, parallel light is made by a lens, and light passing through a drip tube is condensed by the lens to change its light quantity. It was based on the detection of water droplets that had passed through the drip tube. That is, as shown in FIG. 7A, when the output value of the photodiode 54 exceeds a predetermined threshold level, it is recognized that the water droplet has passed. However, since the light-receiving side is a single semiconductor and the amount of light is collected, when the water drops splash on the inner wall of the drip cylinder when it is used for a long time, or the inner wall sticks due to temperature fluctuations. In this case, the amount of light received by the light receiving element is attenuated, for example, as shown in FIG.
As described above, the difference between the voltage level when the water droplet is passing and the voltage level when the water droplet is not passing is small (S / N ratio is reduced), and there is a problem that it is difficult to detect the water droplet.
In addition, there is a problem that erroneous detection occurs due to strong disturbance light such as sunlight directly entering the light receiving element.

Therefore, it has been proposed to recognize droplets as an image using an image sensor. By the way, in a drip detection device using an image sensor, as shown in FIG. 8 (a), the sensor / output is integrated (S1), and when this value exceeds a reference value (S0), it is judged that a droplet has passed. Was there. However, with this method, when the drug solution adheres to the inside of the drip tube, the integrated value increases (S2) as shown in FIG. 8 (b), and the reference value (S0) is maintained even when the droplet is not falling. Since it exceeded, it became impossible to recognize the droplet. That is,
When the liquid medicine adheres to the inside of the drip tube, the signal output of the image sensor increases, and the judgment of the liquid droplet passage is made by integrating the sensor signal. When the reference level of the passage judgment is fixed, the disturbance noise such as the liquid chemical adhered is mixed. In this case, the droplet cannot be normally recognized, and there is a possibility that the droplet cannot be detected.

Therefore, as shown in FIGS. 9 (a) to 9 (c), the present inventor measured the input value (FIG. 9 (a)) from the reference (no droplet) image sensor (FIG. 9 (a)). By subtracting from (b), a method for recognizing liquid droplets has been proposed that eliminates the influence of chemical liquid adhesion and the like as shown in FIG. 9 (c) (Japanese Patent Application No. 2-25).
128).

[0005]

However, the above-mentioned method of recognizing droplets has the following problems.

(1) As shown in FIG. 9 (c), since the liquid droplets are recognized by the level of the signal from the image sensor, when the liquid droplets are erroneously detected by noise signals such as flicker of liquid and external light. There is.

(2) Since the reference value is changed due to rebound and the like after the drop of the droplet, the droplet may be erroneously detected.

(3) Since only the presence of droplets is detected, it cannot be judged even if the droplets are not allowed to flow and are allowed to flow.

The present invention eliminates the above-mentioned conventional drawbacks, and provides a drip detection device capable of surely detecting a drop by changing the state inside the drip cylinder and promptly following the change in the drip state.

[0010]

In order to solve this problem, the drip detection device of the present invention is a drip detection device for detecting a falling water drop, which is a light source and light is taken in the vicinity of the light source. A light emitting means having a light emitting port that emits light in a direction substantially perpendicular to the falling direction, a light receiving side sensor means having an image sensor for receiving the light, and a sum of signal amounts when a drip does not pass through. And a droplet recognizing unit that determines that the droplet has passed when the sum of the signal amounts changes more than a certain value with respect to the reference value.

Here, the droplet recognizing means stops recognizing the droplet for a certain period of time after recognizing the droplet. Further, the reference value is updated every time a droplet passes. Further, a flow rate detecting means for detecting a case of being too early and a case of being too late with respect to the set flow rate is provided based on the recognition of the droplet. Further, a flow release detecting means for detecting the flow release based on a change in the signal amount during a predetermined period is provided.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic configuration diagram of a drip detection apparatus of this embodiment, FIG. 1 (a) is a top view, and FIG. 1 (b) is a front view. The infusion pump is not shown.

The case 1 contains a sensor light source LED 2, a lens 3, an image sensor 5 and a drip control section 6. The case 1 is slidable and has a structure in which the drip tube 4 is sandwiched from both sides. LED2 is the drip control unit 6
It is turned on by a command from. The light emitted from the LED 2 passes through the lens 3 and is emitted in a shape close to a parallel ray, and irradiates the drip tube 4. On the other hand, the image sensor 5
Data is taken into the drip control unit 6 and it is determined based on the data whether or not the water droplet is passing. And
The infusion pump is controlled by comparing the drip interval time according to the flow rate with the actually detected drip interval time.

FIG. 2 is a block diagram showing the construction of the drip control unit 6.

The data from the image sensor 5 is RA as digital data via an input interface 62.
It is stored in the image storage unit 64a in M64. CPU
61 is a timer group 620, a counter group 610, a ROM 63
Threshold group 630 and S0 flag 64 in RAM 64
Using b and b, a drip amount is detected according to a control program stored in the ROM 63, and a signal for controlling the drip amount is output to an infusion pump (not shown) via the output interface 65.

Here, as the counter group 610, a continuous error counter 611 and a quintuple error counter 612 and 1 are used.
There is a / 5 times error counter 613. Timer group 620
, S0 detection timer 621 and quintuple interval timer 62
2 and 1/5 times interval timer 623. As the threshold value group 630, there are a threshold value A (631) and a threshold value B.
There are (632) and a threshold value C (633). These are necessary for the control program of the present embodiment described below, and are changed according to the procedure of the control program, and are not limited to this.

FIG. 3 is a flow chart showing a basic control procedure of the drip control unit 6.

When the power of the drip detection device is turned on, step S
At 31, the CPU 61 tests the ROM 63 and the RAM 64 to perform hardware initialization and software initialization. After that, in step S32, the operation state signal from the infusion pump is received, and if it is stopped, a loop is formed, and if it is started or fast-forwarded, the process proceeds to step S33 to perform the following processing.

At the start or fast-forward state, step S
In 33, it is determined whether or not the flow rate measurement of the infusion pump has been completed. If not done, step S34 is carried out. If it is done, nothing is done and the process jumps to step S35.

Then, in step S35, it is judged whether or not the liquid droplets are connected, and then in step S36, it is judged whether or not the liquid droplets are currently passing and the check of the drip interval. Step S3
In step 7, if the liquid droplets are connected or if the drip interval is abnormal, the process branches to step S38 to stop the infusion pump.

A detailed flow chart of the droplet continuity judgment and the drip interval check is shown in FIGS. 4, 5 and 6.

The signal from the sensor captures a tomographic image of the liquid droplets about every 3 ms, and when the liquid droplets are connected, the image shimmers and vibrates due to the nonuniformity of the fluid. By catching this slight vibration, it is possible to judge the continuous droplets.

The process shown in FIG. 4 is passed every signal output from the sensor (here, every 3 ms). Step S4
In 1, the sum of the changes in the sensor output for the past 5 times is calculated, and when the sum exceeds the threshold value A, the error count is incremented by 1 in step S43, and otherwise the error count is cleared in step S46. . If the error count is incremented, it is determined in step S44 whether or not this has continued B times or more, and in that case, it is determined that it is continuous.
In step S45, the error flag is set. Next, a detailed flow chart of the check of the drip interval shown in FIGS. First, at step S51, the condition judgment of S0 detection is made. Incidentally, S0 is the integrated value of the sensor signal when the droplet is not passing.

When the S0 fetch timer times up in step S52, S0 is fetched in step S53,
At step S54, S0 detected is set. For this reason,
A mask time is set so that droplet recognition is not automatically performed before S0 is captured. When S0 is fetched, the flow advances from step S51 to step S55 to proceed to the droplet recognition judgment.

Here, the period of the sensor output signal (3 m
The output signal is integrated every s), and if this value is S, | S-S0 | and the threshold value C are compared in step S55, and |
When S-S0 | ≥C, the liquid droplet passes, and the process proceeds to step S61 to enter the check at ⅕ times the interval. │S-S0 │ <
If C, proceed to step S56 to check at 5 times intervals.

When | S-S0 | ≥C is satisfied and the 1/5 time interval timer is not 0, the 1/5 time interval error counter of the error that the drip interval is too early is incremented in step S62, If this continues three times in a row, step S63
From S68, the drip error is set. The same applies to the ⅕-time interval check at the 5-time interval check of steps S56 to S60.

If the liquid drops pass and the drip interval is normal, the 1/5 times interval error counter is cleared in step S64, and the S0 detection timer, 1/5 times, in step S65.
Reset the quintuple timer and start it again.
The S0 detected flag is cleared at 66, the S0 detection timer is started at step S67, and the next droplet judgment is made.

[0028]

As described above, according to the present invention, it is possible to provide a drip detecting device capable of surely detecting a drop by changing the state inside the drip cylinder and promptly following the change of the drip state.

That is, even when the liquid medicine is adhered to the inside of the drip tube, the received light image before the drop of the water drop is taken as S0 and compared with the received light image when the drop of the water drop is detected to detect the presence or absence of the drip tube. It is possible to detect drip without being affected by cloudiness or water drops adhering to the inside of the drip tube.

Further, since the droplet is not detected for several 100 ms after the droplet is recognized, a detector that is not affected by the flicker of the droplet, the burrs and the like is provided. Further, since it includes a routine for checking each drip and a routine for detecting the flow release, a drip detection device capable of detecting a flow rate abnormality and monitoring the flow rate is provided.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a drip detection device of the present embodiment.

FIG. 2 is a configuration diagram of a drip control unit according to the present embodiment.

FIG. 3 is a schematic flow chart of a drip control unit.

FIG. 4 is a flow chart showing a procedure for detecting an off flow.

[Figure 5],

FIG. 6 is a flow chart showing a procedure of droplet recognition and droplet interval check.

[Figure 7] ~

FIG. 9 is a diagram illustrating an example of conventional droplet recognition.

[Explanation of symbols]

1 ... Case, 2 ... LED, 3 ... Lens, 4 ... Drip tube, 5
... image sensor, 6 ... drip control unit, 61 ... CPU, 6
2 ... Input interface, 63 ... ROM, 64 ... RA
M, 64a ... Image storage section, 64b ... S0 flag, 6
5 ... Output interface, 610 ... Counter group, 62
0 ... Timer group, 630 ... Threshold group

Claims (5)

[Claims] 1. A drip detection device for detecting a falling water drop, comprising: a light source; and a light emission port that emits light in the vicinity of the light source and emits light in a direction substantially perpendicular to the drop direction of the drip. Means, a light-receiving side sensor means having an image sensor for receiving the light, and a sum of the signal amount when the drip does not pass through as a reference value, and a change of a certain value or more with respect to the reference value causes the signal amount to change. And a droplet recognizing unit that determines that the droplet has passed when the sum of the two drops occurs. 2. The drip detection device according to claim 1, wherein the droplet recognition means stops the recognition of the droplet for a certain period of time after the recognition of the droplet. 3. The drip detection apparatus according to claim 1, wherein the reference value is updated every time a liquid droplet passes. 4. The drip detection apparatus according to claim 1, further comprising flow rate detection means for detecting whether the set flow rate is too early or too late based on the recognition of the droplet. 5. The drip detection device according to claim 1, further comprising a flow release detection means for detecting the flow release based on a change in the signal amount during a predetermined period.