JPH0575623U - Liquid level sensor - Google Patents

Abstract

(57) [Summary] [Purpose] A sensor is provided on the outer peripheral surface of the drip cylinder to detect the liquid level of a drug solution filled in a container such as an infusion bag. [Structure] A medical infusion solution such as a liquid in a hospital is filled in an infusion bag such as polyethylene. The sensor is held near the liquid level detection level on the outer surface of the drip cylinder made of a plastic material arranged in the lower part of the bag, and a plurality of electrodes made of a conductive member are arranged separately from each other in a direction parallel to the liquid surface. The capacitance of the capacitor composed of the electrodes, plastics and chemicals changes depending on the liquid level. The capacitance detected between the electrodes is converted into an electric signal and compared with a predetermined liquid surface level, and the arrival of the liquid medicine in the bag at the liquid surface level can be identified. The sensor can be freely attached to and detached from the outer peripheral surface of the cylindrical container, and it can quickly respond to replacement of the bag and change of the liquid level to be detected, and can automatically notify that the chemical liquid in the bag reaches the liquid level to be detected. . Various dimensions,
It can be applied to shaped infusion containers and is not affected by the dielectric constant of liquids.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to, for example, a liquid level detection sensor for detecting the liquid level of a liquid medicine filled in an infusion container when instilling a patient in a hospital or the like, and particularly to automatic detection of the liquid level from the outer peripheral surface of the container. .

[0002]

[Prior Art]

 FIG. 4 is an explanatory view showing an example of a drip device, 20 is an infusion bag filled with a drug solution for drip, 21 is a drug solution, 22 is a stand, 23 is a drip tube, and 24 is a control tool for adjusting the drip amount. , 25 are venous needles.

The conventional drip device is configured as described above, and the bag 20 filled with the drug solution 21 suspended on the stand 22 is usually placed on the bedside of the patient. The drug solution 21 in the bag 20 is supplied to a drip tube 23 of a transparent container, and further injected into a patient's vein by a venous needle 25 via an adjusting tool 24. The adjuster 24 adjusts the drip amount while observing the state of the drip in the drip tube 23. The liquid level of the drug solution 21 in the transparent bag 20 is visually monitored by the patient, and when the liquid level drops, the patient operates a push button or the like to notify the central control room or the like of this.

[0004]

[Problems to be solved by the device]

 In the conventional drip device as described above, the drop of the liquid level of the drug solution 21 in the transparent bag 20 for drip is visually informed by the patient. Therefore, patients cannot rest comfortably because they must constantly monitor the liquid level. When the patient falls asleep, he / she does not notice the decrease in the liquid level and cannot correctly inform the liquid level.

If the drug solution 21 in the bag 20 is exhausted, the blood in the vein may flow back into the pipe, further exacerbating the medical condition of the patient. In addition, since there is an individual difference in notifying the liquid level of the drug solution 21 via the patient, it is not possible to always notify an appropriate liquid level, so that there is a waiting time for the replacement of the bag 20 and work efficiency decreases. There was a problem to do.

The present invention has been made in order to solve such a problem, and the notification of the liquid level of the liquid medicine 21 in the bag 20 can be automatically performed without the intervention of the patient so that the patient can rest in peace. The purpose of the present invention is to obtain a liquid level detection sensor that can promptly and appropriately respond to replacement of the bag 20 and change of the liquid level detection level and can contribute to safety and efficiency improvement of drip.

[0007]

[Means for Solving the Problems]

 The liquid level detection sensor according to the present invention is a holding member that is formed into a cylindrical shape and has elasticity in its radial direction by cutting out a part, and a conductive member that is attached to a part of the inner peripheral surface of the holding part through a cushioning material. And a second electrode formed of a conductive member that is isolated from the first electrode and has the same potential as the holding portion and is attached to the inner peripheral surface via a cushioning material, and the holding portion and the first electrode. A coaxial cable electrically connected is provided.

[0008]

[Action]

 In this invention, a plurality of electrodes made of a conductive member are separately arranged on the inner peripheral surface of a holding portion made of a cylindrical elastic member with a buffer material interposed therebetween, and one electrode is electrically connected to the holding portion and the other electrode is made. In the sensor that outputs a signal by connecting a coaxial cable to the electrode and the holding part, both electrodes are electrically shielded by the holding part, and the holding part can be detachably attached to the cylindrical container by its elasticity.

A drug solution used for drip infusion to a patient is filled in an infusion bag such as polyethylene, and a transparent drip tube made of a plastic material is arranged below the bag. The drip cylinder is always used to store the drug solution up to a half quantile, and the sensor is attached so that the holding part made of an elastic member is located below the liquid level of the drug solution on the outer surface of the drip cylinder. Capacitors made of electrodes, plastics, and chemicals change their capacitance depending on the liquid level.

The capacitance detected from one of the electrodes and the holding portion is converted into an electric signal and compared with a predetermined liquid level in the drip cylinder. From the change in the capacitance, a predetermined liquid level of the drug solution in the drip cylinder is determined. Reaching the level can be identified. The sensor can be freely attached to and detached from the outer peripheral surface of the drip tube, allowing quick response to bag replacement and changes in the liquid level to be detected. The arrival of the liquid level in the drip cylinder at the predetermined liquid level can be automatically notified.

[0011]

【Example】

An embodiment of the present invention will be described in detail with reference to the accompanying drawings. 1 is a sectional view of an essential part showing an embodiment of the present invention, FIG. 2 is a side view of FIG. 1, and 1 is a sensor, 2 is an elastic holding part, 3 is a bent part, and 4 is a first electrode. , 5 is a second electrode, 6 is an electric connection terminal provided on the electrode, 7 is a coaxial cable, 8 is a cushioning material, 9 is a seat provided on the holding portion 2, 10 is a fastening tool for fixing the coaxial cable 7, Reference numeral 11 indicates a reinforcing plate.

In the liquid level detection sensor configured as described above, a conductive plastic, a metal plate, and a conductive material obtained by compounding carbon black, a conductive filler such as metal powder or carbon fiber, with a base material such as rubber or plastic are used. For example, for a rectangular electrode using a conductive member such as a conductive film, a metal terminal 6 is caulked to the end of the first electrode 4, and the second electrode 5 is connected to the holding portion 2 made of an elastic member such as phosphor bronze. They are electrically connected to each other and arranged in parallel to the holding portion 2 via a cushioning material 8 such as a foam material.

The coaxial cable 7 fixed to the holding portion 2 with the fastener 10 is electrically connected to the first electrode 4 via the terminal 6 and to the second electrode 5 via the holding portion 2, respectively. Both electrodes are arranged so as to be covered by the holding portion 2, and the holding portion 2 has the same potential as the second electrode 5 and acts as an electric shield for both electrodes. The holding portion 2 is provided with a reinforcing plate 11 or the like on its outer peripheral surface, and even if the notch is manipulated and deformed around the bending portion 3 as a fulcrum, the holding portion 2 returns to a predetermined shape due to elastic restoring force. Therefore, it is possible to obtain the sensor 1 which is detachably attached to the cylindrical container having various sizes and in which the flexible electrode is in close contact with the outer peripheral surface of the container through the cushioning material 8.

FIG. 3 is a block diagram showing an example of sensor instrumentation, 1 , 2, 7 , 9, 10 , 21, 23 are the same as the above example, and 12 is a signal conversion for converting the capacitor capacitance into an electric signal. Reference numeral 13 is a charging / discharging circuit, 14 is a shaping circuit, 15 is an integrating circuit, 16 is a setter, and 17 is a comparator.

In the liquid level detection sensor configured as described above, the sensors 1 held by the elasticity of the holding portion 2 on the outer peripheral surface of the drip tube 23 of the plastic material filled with the chemical liquid 21 are arranged in parallel. A plurality of electrodes are arranged so as to be parallel to the liquid surface, and the first electrode 4 and the second electrode 5 respectively form a capacitor by the plastic of the drip tube 23 and the conductive chemical liquid 21, and each capacitor forms the chemical liquid 21. Are connected in series via. Therefore, the capacitance of the capacitor is derived from the holding portion 2 electrically connected to the first electrode 4 and the second electrode 5.

The capacitance from the sensor 1 is connected to the signal conversion circuit 12 via the coaxial cable 7, and the charging / discharging circuit 13 performs charging / discharging at a cycle proportional to the capacitance. The shaping circuit 14 shapes the pulse generated in each charge / discharge cycle into a pulse waveform with a constant amplitude and duration, and the integrating circuit 15 converts the pulse into an average DC voltage, which is proportional to the charge / discharge cycle. Obtain the electrical signal. The electric signal is compared with the set level of the setter 16, and the level of the chemical liquid 21 is detected by the comparator 17.

However, when the drip progresses and the liquid level of the drug solution 21 falls below the position of the sensor 1 provided in the drip tube 23, the capacitance cannot be obtained and the function of the capacitor is lost. Therefore, the decrease in the liquid level of the chemical liquid 21 can be clearly identified. The detection operation is not affected even if the type of the chemical liquid 21 is different.

As described above, by using the sensor 1 which is detachably attached to the drip tube 23, the liquid level of the drug solution 21 in the drip tube 23 can be automatically detected without the intervention of the patient. Furthermore, it is possible to quickly respond to replacement of the bag 20 and change of the liquid level to be detected.

Since the holding portion 2 covers the first electrode 4 and the second electrode 5 to shield them electrostatically, the capacitance of the capacitors formed by the respective electrodes can be avoided from interference by the human body, and the liquid dielectric Sensor with high reproducibility and stable operation because it is not related to the rate 1 Is obtained. Therefore, infusion of saline and glucose can be safely, properly and efficiently performed. Further, as the area of the electrode increases, the capacitance of the capacitor increases, so that the detection sensitivity can be improved.

[0020]

[Effect of the device]

 As described above, the present invention is such that a plurality of electrodes made of a conductive material are arranged side by side on the inner peripheral surface of a cylindrical holding portion having elasticity, and the electrodes are partially notched. With a simple structure that is placed so as to be covered with the liquid, the liquid level is automatically notified without the intervention of the patient, and safe and appropriate infusion can be performed. It is detachably installed on the outer peripheral surface of the container without being immersed in the liquid in the container, and can quickly respond to bag replacement and change of the liquid level to be detected. It has the effect that it can be used for infusion containers of various materials, sizes and shapes, and for detecting the liquid level of various conductive liquids.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part showing an embodiment of the present invention.

FIG. 2 is a side view of FIG.

FIG. 3 is a block diagram showing an example of sensor instrumentation.

FIG. 4 is an explanatory diagram showing an example of a drip device.

[Explanation of reference numerals] 1 sensor 2 holding portion 3 bending portion 4 first electrode 5 second electrode 6 terminal 9 seat 10 fastener

Claims (3)

[Scope of utility model registration request] 1. A liquid level detection sensor for detecting a liquid level of a conductive liquid filled in an infusion container, wherein a holding portion formed in a cylindrical shape and having elasticity in a radial direction thereof is partially cut away. A first electrode made of a conductive member adhered to a part of the inner peripheral surface of the holding member via a cushioning material, and having the same potential as the holding portion separated from the first electrode and having an inner peripheral surface via the cushioning material. A liquid level detection sensor comprising a second electrode made of a conductive member attached and a coaxial cable electrically connected to the holding portion and the first electrode, and detachably attachable to a cylindrical container. 2. The liquid level detection sensor according to claim 1, wherein the conductive member has flexibility. 3. The liquid level detection sensor according to claim 1, wherein the cushioning material is a foam material.